Practically double-posting but I whipped this together quick after seeing the trend. Took a rare Arcana and a pretty powerful Persona, but anyways...

Persona: Echidna
Personality: Born of the "Faith" Arcana, Echidna represents belief in oneself and others. Being the child of the gods of the sea and the mother of all monsters, Echidna is one who puts her faith in her children, her creations. Nonetheless, she is the mother of [i]monsters[/i], and can represent that role quite well.

Ultimate Form: Tiamat, the personification of salt water and primordial chaos. Another mother of monsterkind, Tiamat can be considered one that does not deserve trust as the inverse of the "Faith" Arcana might represent.