Celia

Celia (Seria) セリア is one of two Ultima Demons disguised as human females in Final Fantasy Tactics. She and another such demon, Lettie, serve as assistants to Zalera, who had possessed Marquis Elmdore. Celia is the assassin wearing blue.

Riovanes Castle
Celia assisted Marquis Elmdore in re-retrieving the Scorpio stone, which was held by Marach Galthena at Riovanes Castle. After Rapha, Marach's sister, who was Ramza's friend, took the stone, Celia ambushed Rapha and Ramza on the castle roof with Elmdore and Lettie. Ramza defeated the trio, causing Elmdore to make a tactical retreat.

Limberry Castle
Celia, Lettie, and Elmdore set up base at Limberry castle. Ramza believed Alma to be at Limberry, so he headed to the castle. Celia attacked him at the gate with Lettie. Ramza defeated the assassins again, forcing them to flee inside. In the castle, they alerted Elmdore of Ramza's coming. Before Elmdore could react, Ramza arrived. Celia, Lettie, and Elmdore all attacked him. Celia and Lettie revealed their Ultima Demon forms, but were defeated again and finally killed.

Boss
Celia is fought three times in the story; once at Riovanes Castle and twice at Limberry Castle. She starts at level 29 with 65 Bravery and 70 Faith, and comes equipped with the two Kiyomoris, Black Cowl, Cachusha, and a Gaia Gear. She has access to the Subdual Arts command as well as Move +1, a random action ability, and random Squire abilities. In this battle, she is immune to Stone, Chicken, and Toad.

Celia