From Final Fantasy Wiki

Siren uses Lunatic Voice against the enemy party, in Final Fantasy VI

Siren (セイレーン, Seirēn) is a recurring summon in the Final Fantasy series. It is often portrayed as a beautiful woman who plays a harp. Her attacks usually focus on inflicting Silence on the opponent, but they sometimes also do minor damage.

Appearances

Final Fantasy VI

Siren is one of the first Espers obtained. She costs 16 MP to summon. Her attack, Lunatic Voice (Hope Song in the original version), has a Hit Rate of 136. She teaches the following spells:

• Sleep x10
• Mute x8
• Slow x7
• Fire x6

At Level Up, she provides a +10% boost to HP.

This is the first time she appears as a summon. It is worth noting that she has three sprites as in the American version her exposed rear was censored, and a third sprite was used in the Advance release (shown above), less revealing than the original Japanese sprite and more revealing than the original American sprite.

Final Fantasy VIII

See the Summon sequence here

The Siren (Japanese セイレーン Seirēn; French Ondine) is a Guardian Force. It is obtained by Drawing from Elvoret at the top of the Dollet Radio Tower during the SeeD field exam. Its attack Silent Voice deals non-elemental damage as well as inflicting Silence status to all enemies.

This is her first time in a 3D Final Fantasy.

Abilities learned from Siren listed below:

Triple Triad

Siren
	Level	8 (GF Card)	Element	Water
	Refine	1 refines into 3 Status Atks
	Drop	n/a
	Card	n/a
	Win	Pub Manager in Dollet, after the first card game

Final Fantasy XII: Revenant Wings

Main article: Siren (Revenant Wings)

"Irresistible songstress who beguiles eye and ear alike."

—In-Game Description

Siren is the rank 2 Water Aerial summon. Her normal attack, Kickline Dance, has the ability to inflict Stop. She has no special attack. Her appearance follows that of the Sprite enemy in Final Fantasy Tactics Advance.

Final Fantasy XIII

Siren in Final Fantasy XIII

Siren makes a minor appearance during the Eidolon show in Nautilus.