The Teen Titans were a team of young super-heroes who were the former sidekicks to older, more experienced heroes. They first came together when Robin, Aqualad and Kid Flash responded to an emergency taking place in the hamlet village known as Hatton Corners. There they fought a mysterious villain calling himself Mister Twister. After defeating Mister Twister and robbing him of his elemental powers, the three young heroes decided to band together as the Teen Titans. This decision was supported by their respective mentors, Batman, Aquaman and the Flash.
Their first actual mission as the Teen Titans also yielded the team’s first recruit – Wonder Girl. Donna Troy was a young heroine raised on Paradise Island under the tutelage of her mentor Wonder Woman and Wonder Woman’s mother Queen Hippolyta. Another charter member was Roy Harper, the archer known as Speedy. Though present since the team’s inception, Speedy did not always attend team meetings or share in all of their adventures. Their first adventure brought them to the town of Midville where they fought against Jake Trask – the Separated Man. The Separated Man had been terrorizing the town's "Teen Government for a Day" Project.  Subsequent adventures brought them into conflict with a band of criminals impersonating a pop band named the Flips  as well as a giant robot known as El Conquistadore.  After unveiling the mystery behind the so-called "Beast-God of Xochatan", the Titans established themselves in their first headquarters – Titans Lair.  Titans Lair was an underground facility that once served as a records storage warehouse for Wayne Enterprises. The team prospered and went on to encounter several strange villains such as car-club hot-rodder Ding Dong Daddy and Carnaby Street fashion designer the Mad Mod.
In time, the Teen Titans met a millionaire industrialist named Loren Jupiter.  Jupiter was putting together a training program designed to help young heroes work within a team dynamic. The Titans agreed to work under Jupiter’s tutelage and met several more heroes who would eventually become part of the team. While pursuing criminals linked to the NG3 organization (secretly backed by aliens from Dimension X), the Titans met the heroes Hawk and Dove who had likewise been on the trail of NG3 leader "The Fat Man". Hawk and Dove would soon become close allies as well as team members. Also at this time, the orphan empath Lilith Clay joined Loren Jupiter's organization as well as amateur boxer Mal Duncan. One of the more bizarre heroes to join the Teen Titans was the time-lost cave boy Gnarrk. Gnarrk formed an empathic bond with Lilith Clay and the two later became lovers.
When a being known as Raven sends out a distress call for Robin (Dick Grayson), Kid Flash (Wally West), Wonder Girl (Donna Troy), Cyborg, Beast Boy, and Starfire the teens band together as the NEW Teen Titans to fight Trigon, Raven's demond father.
After defeating the being, Trigon, the teens banded together as the official second Teen Titans team!
The Team Titans hailed from a near-distant alternate future where they functioned as an analog to the modern day Teen Titans. When a villain known as Lord Chaos became the supreme monarch of the future, the Titans discovered that the only way to stop him was to travel backwards in time and prevent the circumstances which led to his birth. They discovered that Lord Chaos was the son of Donna Troy and her husband Terry Long. Donna Troy, naturally refused to take any course of action that would lead to her child's death, and elected instead to excise her own powers, so that the child would not inherit any superhuman abilities of his own. With the exception of Mirage and Terra, the future timeline of the Team Titans was erased from existence following the events of "Zero Hour".
It was also during Zero Hour that long-time Justice League member, the Atom, was regressed in age to the physical age of seventeen. This chronal alteration would soon after draw the Atom into the Teen Titans legacy.
A small contingent of Psions were captured and enslaved by an alien race known as the H'San Natall. It was the H'San Natall's intention to seed the planet Earth with various sleeper agents whose bodies would be genetically modified to harness great power and fight against Earth's superhuman populace. The H'San Natall enslaved a number of Psions and put them to work bringing their plans to fruition from a laboratory on the moon of Titan. For sixteen years, the Psions monitored the progress of eight genetically altered humans, one of whom, Audrey Spears, was raised in a virtual reality chamber on Titan. Audrey, and three other of her fellow seeds escaped Titan with the help of the (now teenaged) hero known as the Atom. Kidnapping a Psion scientist named Dorek, they returned to the world of their birth and became the second group of young heroes to call themselves the Teen Titans. 
This group of Titans consisted of five initial members:
Their first mission as a team pitted them against Pylon and his organization, the Veil. Pylon's goal was to study and eradicate all alien lifeforms from the planet Earth, regardless as to whether or not they posed a viable threat. He had managed to capture the alien savage known as Fringe, as well as Supergirl. The Teen Titans teamed up with Nightwing, Robin and Captain Marvel, Jr. to rescue them. Through this, the Titans learned that Fringe was an experiment of the H'San Natall as well. 
Soon after, the Titans encountered their first super-villain, Dark Nemesis. Dark Nemesis had been hired by Pylon to capture the Titans so that he could study their powers. The villains baited the Titans into a trap at the Mall of the Universe in Minneapolis, Minnesota. The Titans lost their first battle against Dark Nemesis and they were captured and imprisoned inside containment cubes designed to negate their powers. The Atom however, succeeded in freeing them, and the Titans fought back, ultimately defeating their adversaries. 
This event immediately led the Titans on a journey to the lost world of Skartaris to rescue their missing teammate, Prysm. During this adventure, the Titans teamed up with Warlord Travis Morgan and his wife Queen Tara against the forces of the evil sorceress, Motalla. They succeeded in rescuing Prysm as well as Warlord's daughter, Jennifer Morgan.  On their way home from Skartaris, the Titans made an impromptu stop at Lost Junction, Canada, where they were forced to contend with a community of cannibals. 
The Titans is made up of ex-members of the Teen Titans who have passed the maximum age limit to be able to join the Teen Titans. Dick Grayson was a Teen Titan member as Robin, Wally West as Kid Flash, Roy Harper as Speedy. The other members have remained with the same identity from childhood to adulthood
The deaths of Lilith and Donna Troy resulted in the dissolution of both the Titans and Young Justice. From this tragedy however, a new incarnation of the team emerged, once again calling themselves the Teen Titans. The initial roster for this team consisted of three veteran Titans: Changeling (now calling himself Beast Boy once again), Cyborg and Starfire. Four members of the defunct Young Justice were brought in as their charges: Robin, Impulse, Superboy and Wonder Girl. Cyborg was tasked with training the younger heroes in the tradition of the Titans. To this end, he designed and built a new Titans Tower located in San Francisco, California.  The first foe to face this new team of Titans was their old adversary Deathstroke. Deathstroke however, was actually possessed by the spirit of his late son Jericho. Controlling Deathstroke's body, Jericho wanted to make an example of the Teen Titans to prove to the world that kids shouldn't wear costumes. During this conflict, Jericho/Deathstroke succeeded in crippling the speedster Impulse. Though he quickly recuperated, the experience forced him to appreciate the tradition of the Titans legacy, so he changed his code name to Kid Flash after former Titan Wally West. The Titans succeeded in driving Jericho out of Deathstroke’s body whereupon they downloaded his essence onto disk drive which they secured away inside the Tower. 
Their next trial brought them against another former adversary of the New Teen Titans – the Church of Blood. The High Priest of the Church of Blood was a sixteen-year-old boy named Sebastian who ascended to the post (as per the tradition of the cult) through patricide. As the new Brother Blood, Sebastian captured former Titans member Raven. It was at this time that the cult was revealed to be worshipers of Raven's demonic father Trigon. In an occult ritual, Brother Blood wed Raven and sought to claim her power as his own. The Teen Titans fought against the Church of Blood and Raven was freed. Reborn into a younger human body, Raven rejoined the Teen Titans. Shortly after this adventure, Starfire left the group to join the Outsiders, but still teamed up with the Teen Titans on a regular basis. 
Shortly thereafter, a man from Beast Boy's past named Doctor Samuel Register attempted to replicate the conditions that produced Beast Boy's ability to change into different animals. Calling himself the Zoologist, he released a virus that transformed dozens of San Francisco children into animals. Register infected himself with the rare Sakutia virus that once affected Beast Boy and gained the ability to turn into a wide array of animals (albeit purple in color). Beast Boy and the Zoologist fought one another and Garfield eventually defeated him. An antivirus was created and released into the atmosphere turning all of the children back to normal. 
The Teen Titans' next adventure brought them one-thousand years into Earth's future. They teamed up with the Legion of Super-Heroes to battle a five-hundred member strong army of the Fatal Five. The Fatal Five-Hundred (as they were called) were made up of one-hundred versions of the team, all of whom hailed from alternate dimensions. During the battle, Superboy used the Persuader's Atomic Axe to open a rift, sending all of the dimensional counterparts back to their dimension of origin. As a result however, the Legion likewise were lost to infinity.  While attempting to return to home, the Titans were sidetracked to an alternate timeline some ten years into the future of their normal timeline. Here they met older versions of themselves who had since adopted the legacies of their heroic forbearers. Unlike the real Teen Titans however, these "Titans of Tomorrow" had abandoned their previous ideals of heroism and adopted a might makes right attitude towards crime-fighting. Robin in particular was disgusted when he discovered that his older self was murdering criminals with a handgun while donning the name and costume of Batman. The Teen Titans met with a renegade group of former Titans from this timeline who referred to themselves as Titans East. The members of Titans East still maintained a sense of virtue and helped the time-lost Titans return to their own era by way of a Cosmic Treadmill. 
Robin was not the only one adversely affected by his experiences in the future. Superboy, who had for some time been wrestling with the truth that he was a partial clone of Lex Luthor, was greatly bothered to see his future self engage in acts of such wanton violence. Superboy’s apprehension proved justified when his teammates discovered that Lex Luthor had programmed a psychic trigger into his genetic make-up that caused him to turn into a violent, robotic drone. Under Luthor’s control, Superboy attacked his teammates, greatly injuring his girlfriend Wonder Girl in the process. It took the full might of both the Teen Titans and the Outsiders to halt Superboy’s rampage. Ultimately, Superboy returned to normal, but the damage to his psyche was grave. 
During this time, the Teen Titans accepted several new members into their ranks. The first was Mia Dearden, who had only recently taken up the mantle of Speedy, a name previously used by veteran Titan Roy Harper. They also recruited Dawn Granger, the second hero to uphold the name of Dove. Complimenting Dove was her sister Holly who assumed the role of Hawk. Hawk and Dove began their short tenure with the team during a massive battle in Philadelphia against another old Titans foe Doctor Light.
The Teen Titans played an integral part in a planetary catastrophe that has come to be known as "Infinite Crisis". During the Battle of Blüdhaven, Superman hand-picked Robin to coordinate rescue efforts in the beleaguered city after it had been attacked by Chemo. Several times during this crisis, the Titans found themselves in pitched battle against the insane Superboy of Earth-Prime. Their fight against Superboy-Prime came at great cost, when the bloodthirsty Kryptonian brutally slaughtered several former Titans including Baby Wildebeest, Bushido and Pantha. Risk was also seriously maimed when Prime tore his arm off and would have died from substantial blood loss if not for the efforts of Raven. The Titans' greatest loss however was when one of their own, Superboy, sacrificed his own life to stop the machinations of Superboy-Prime's puppet master, Alexander Luthor. A special memorial to Superboy was erected in Centennial Park in Metropolis next to the one honoring Superman. 
The death of Superboy caused a dramatic shake-up in the team roster. Cyborg had been injured during the Crisis, Starfire was missing in action and Raven had departed from the team for a special mission. Beast Boy left the group to rejoin his original outfit the Doom Patrol. Kid Flash disappeared into the Speed Force during the Crisis and had come back four years older and seemingly powerless. Hawk and Dove had quit and Speedy left the team for a six-month training session on the Marshall Islands with her mentor Green Arrow. Robin, still reeling from the aftershocks of Superboy's death, tried in vain to re-clone him from skin samples he had obtained. Each effort however, met with failure. To fill the vacuum left behind by the absent Titans, Robin and Wonder Girl began auditioning new members. Several neophyte heroes tried out for the roster including Molecule, Little Barda, Miss Martian and Zachary Zatara. At this time, Deathstroke's daughter Rose Wilson, having abandoned her chosen career as a criminal, was accepted into the ranks of the Teen Titans as well. Wonder Girl however, did not support Rose's inclusion on the team, and the two continue to despise one another to this day. Of those that tried out, the only other member who remained with the team was the young alien Miss Martian.
The Titans tried to track down Raven who had been missing ever since the Crisis. Their efforts led them halfway across the world where they had encounters with Russian super-agent Red Star and the atomic heroine Bombshell. At this time, Brother Blood returned to menace them and once again tried to claim Raven as his own. During the ensuing fight, Bombshell revealed herself as a traitor, and Miss Martian proved her loyalty to the Titans by fighting valiantly against her. When the debacle against Brother Blood concluded, the reason behind Raven's disappearance became known. Having taken the disk containing the life energy of Jericho, she used magic and Brother Blood's Pool of Blood to resurrect Jericho in a new body. Free of the evil impulses that once dominated him, Jericho returned to Titans Tower as a normal human being. 
Jericho's father Deathstroke soon learned of his son's resurrection and sought to make sure that both Rose and he had a place amongst the Titans. In order to facilitate a suitable family environment for his offspring, Deathstroke engaged in an elaborate scheme to force the Titans to accept Rose and Joey into their ranks. To this end, he recruited several super-powered individuals into a new Titans East. Titans East and the Teen Titans battled one another in a fight that brought them all the way back to New York and the original Titans Island. In the end, the Titans proved victorious, but Deathstroke managed to elude capture. Neither Rose nor Jericho learned of the true motivations behind their father's actions.
This was also the period when two more former Titans lost their lives through acts of violence. A rogue Monitor named Solomon assassinated Duela Dent, the Titans West member who once called herself the Joker's Daughter. It was discovered at this time that Duela was actually an anomaly from a divergent reality designated Earth-3.  Likewise, Bart Allen returned from the Speed Field now physically older than he was when he first entered it. After a very brief stint as the Flash, Bart was murdered by the Rogues Gallery. 
In the midst of unending chaos and death, two more members joined the Teen Titans. Kid Devil, former sidekick to Shadowpact member Blue Devil, joined the group shortly before the battle with Titans East. Supergirl also joined the team, but her actions following the "Amazons Attack" incident caused a rift between Wonder Girl and she and she left the team after only a few adventures. Jaime Reyes, the new Blue Beetle began associating with the Titans, but has not officially joined the team.
The Titans later participated in a second confrontation with the Titans of Tomorrow, this time accompanied by the cosmic threat of Starro. They also crossed paths with a new team of young villains called the Terror Titans.
A second team consisting of the older Titans formed shortly after the Teen Titans' battle against Starro and the Titans Tomorrow. Having distanced himself from the San Francisco team, Cyborg began recruiting young heroes into a new iteration of Titans East. Some members such as Anima had served with the roster in previous incarnations. Others, were amateur heroes like Power Boy and Little Barda who had little experience working with a team dynamic. Cyborg suspected that Power Boy was dangerous and primarily invited him to the group so he could keep an eye on him. During a training exercise on Titans Island, a mysterious assailant attacked the neophyte heroes and Power Boy was killed in the onslaught. Other recruits such as Hawk and Dove and Lagoon Boy were also greatly injured.  News of this incident reached the former members of the New Teen Titans and the heroes reformed the Titans to investigate the matter. They soon discovered that the threat originated with the spawn of one of their most dangerous foes ever – Trigon. 
Shortly after the "Final Crisis" event, the Teen Titans experienced another major roster shake-up. Long-time leader Tim Drake quit the team in the wake of the apparent death of his mentor, Batman. The reigns of leadership were handed over to Wonder Girl who had an open enrollment session, in search of new members. Many of those who arrived for the membership drive involved neophyte heroes who were formerly prisoners of the Clock King and brainwashed into participating in gladiatorial combat at the Dark Side Club. After carefully analyzing all of the potential recruits, the final roster consisted of: Wonder Girl, Aquagirl, Blue Beetle, Bombshell, Kid Eternity, Miss Martian, Ravager, Static and a now-powerless Eddie Bloomberg. 
Immediately after its formation, the Teen Titans teamed up with their older East Coast counterparts, the Titans, in order to stop an insane Jericho from killing dozens of people in a trendy New York restaurant. This debacle also brought the Teen Titans into conflict with a new Vigilante, who had been operating in New York and Gotham City for several months. Both teams succeeded in defeating Jericho, but it was the Vigilante who dealt the villain a crippling blow by removing his eyes – the source of his powers.
Shortly after this "Deathtrap" affair, Ravager reevaluated her position on the team. Although she had developed close ties with Eddie Bloomberg, she was not particularly well-liked by her peers and often came into conflict with Wonder Girl and Bombshell. Ravager decided that it would be better served to leave the team and she struck out on her own. 
Teen Titans I (1966-1978)
The original team of Teen Titans were the sidekicks of the major superheroes in the Justice League of America. The original team consisted of Robin, Wonder Girl, Kid Flash, Aqualad, and at times Speedy (Speedy was considered more of a special guest hero until the latter part of the series).
The original team first appeared in Brave and the Bold #54, which the Teen Titans were only Robin, Kid Flash, and Aqualad in which they fought Mister Twister. At the end of the issue, the group decided to become a team. Then in Brave and the Bold #60, they decided to add Wonder Girl. Finally, the last appearance before Teen Titans had it's own comic book, was Showcase #59. A few months after this issue was released, Teen Titans officialy became it's own comic book.
In 1973, the book was cancelled with issue Teen Titans #43. Finally, after three years of fans wanting the book to come back, Teen Titans started back up with issue #44 of November of 1976. The book lasted two more years, with the addition of Bumblebee, Bat-Girl (Bette Kane), and Golden Eagle. The book ended with issue #53 in 1978.
New Teen Titans (1980-1996)
After the original series of Teen Titans ended in 1978, a new team of Titans were introduced in DC Comics Presents #26. The new team of Teen Titans in this issue were Robin (Dick Grayson), Kid Flash (Wally West) and Wonder Girl (Donna Troy).
A few months after this preview was released, the series began with writer Marv Wolfman and artist George Pérez. When the book started in November of 1980, the team of Teen Titans were Robin (Dick Grayson), Wonder Girl (Donna Troy), Kid Flash (Wally West), Changeling, Cyborg, Starfire and Raven. The team started when Raven needed help to destroy her father, Trigon. After they beat him, the team remained together.
The teams first villain after Trigon was Deathstroke the Terminator, who had a contract to kill the Teen Titans. After a while, Deathstroke got help from a girl named Terra, to spy on the Titans and get all the info he needs to destroy the team. Terra betrayed the Titans and then eventually died after being confused about what's going on.
Team Titans (1992-1994)
Team Titans was a series based off The New Titans that lasted only 24 issues. The Titans in this book was nothing like the teams that people has seen in the past. The team consisted of Terra, Killowatt, Dagon, Prestor Jon, Redwing and Battalion. But in Zero Hour, Killowat, Dagon, Prestor Jon, Redwing and Battalion were erased from history, thus ending the series.
Teen Titans II (1996-1998)
Just like the Team Titans book, this book was unpopular and lasted twenty-four issues. None of the members had any relation to the original Teen Titans. that adding Captain Marvel Jr. was added to the team, but the sales didn't go up when he joined and the book ended in 1998 with issue 24.
The Titans (1999-2002)
This team consisted of the original team and some of other teams. The team conisted of Nightwing, Donna Troy, Arsenal, Flash (Wally West), Starfire, Cyborg, Beast Boy, Damage and Argent. This was book lasted 50 issues and was very popular. Between Teen Titans vol. 2 and The Titans, a group called Young Justice was formed.
Young Justice (1998-2003)
This team was a similar group of the original Teen Titans. Young Justice consisted of Robin, Superboy, Impulse, Wonder Girl (Cassie Sandsmark), Arrowette, Empress, Secret, Flamebird, Batgirl, Beast Boy, Lagoon Boy, Lil' Lobo and The Ray.
Both The Titans and Young Justice split up during The Titans/Young Justice: Graduation Day special in 2003. During Graduation Day, Donna Troy and Lillth died. For more info on Young Justice, go to the Young Justice page on Wikipedia.
Teen Titans III (2003-2007)
The Outsiders had Nightwing and Arsenal leading the team. The old team (Batman and the Outsiders instead of Nightwing and the Outsiders) returned the Outsiders were doing great. When Nightwing took a break for awhile and the Outsiders let in Captain Marvel Junior. This series of Teen Titans was started by Geoff Johns as the writer, and artist Mike McKone. The original lineup of the current series consisted of Starfire, Raven, Kid Flash, Robin (Tim Drake), Wonder Girl II, Cyborg, Superboy and Beast Boy. Starfire left in the middle of the series, being replaced by Speedy in issue 21. Superboy left the team in issue 26 and died in Infinite Crisis #6.
One Year Later
After Infinite Crisis and World War III, "One Year Later" started with a new team of Teen Tians. The team started out as Robin, Wonder Girl, Cyborg, Ravager, and Kid Devil. Robin was trying to clone Superboy, but to this date, all of Robins' attempts have failed. Wonder Girl officialy joined the new team in issue 38. The first arc after OYL started was Titans Around the World in which they were trying to find Raven. Also, they was a traitor who was working for Deathstroke. The team found out that the traitor was Bombshell and was almost killed by Ravager. The most current story arc was Titans East in which Deathstroke put together a team of villains to get Ravager and Jericho (his kids) back to his side. In issue 45, Duela Dent helped the Titans, turning into a hero. Batgirl came out of her craziness that Deathstroke put in her. Nightwing, Donna Troy, Flash IV (Bart Allen), Raven, Cyborg and Duela Dent helped the Titans beat Titans East. When the Titans East team were defeated, Intertia helped Deathstroke escape.
In Countdown #51, Duela Dent was killed by a monitor and a funeral was held in Countdown #48 and Teen Titans #47. Jericho took control of Match, a Titans East member, and is believed to be Conner Kent inside of Match. A clue that might be Conner in Match is when he yelled "Wonder Girl!" in Teen Titans (Volume 3) #47. Jericho couldn't control the power of Match and when Wonder Girl tries to get over Conner, she has to face Match and tell him to stop. She says, "It's okay Match. It's me." When she says that, Jericho takes control of Match's body again.
Holy anachronisms, Batman!
This article is in need of updated information.