Valkyrie Profile: Lenneth Valkyrie - Trading Arts (Square Enix)

Lenneth, also known as Lenneth Valkyrie, or sometimes by her epithets of Valkyrie or Battle Maiden is one of the main protagonists from Valkyrie Profile, a game series developed by tri-Ace and published by Enix (now known as Square Enix). She has also appeared in the Final Fantasy series and related titles in multiple forms.

Lenneth appeared as a light-elemenal summon in the original free-to-play version of Final Fantasy Dimensions II. Two versions of Lenneth were available in the game for players to obtain through various means and her outfit was also available as a costume for certain characters.
Similar to other cameo characters, the Lenneth summons and costume were removed from the premium release of Final Fantasy Dimensions II. 

As a usual gimmick from tri-Ace she has made repeated appearances in several of their games, as a recruitable character, boss encounters and cameos referencing her, arguably becoming tri-Ace's most recurring character.