Trista Windell, also known as the Wind Caller Priestess, is the Sage of Wind and Isaac's companion throughout the game. She has medium length red hair and wears a robe like the other Sages.
She literally falls from the sky and lands on Isaac early in the game. She meets his "grandmother", Hanna Arlent, but moments later is attacked by the Diva of the Twilight. Although Hanna is not saved, she does manage to teleport herself and Isaac out of danger. Later on, she is kidnapped by the Lord of the Summer Haze in order to create "Damsel in distress" situation, but she is rescued. Towards the end of the game, it is revealed that the Diva of the Twilight is actually Trista's sister, Seneka Windell. The Diva holds Trista hostage and demands Isaac's Wand in exchange for Trista's life. Trista's later outcome is dependent upon this choice; see the Isaac Lightbrad article for the different endings possible. If the canonical ending is followed, Trista survives and saves her sister from evil.
She seems to have a small crush on Leonard Davia, as she frequently blushes when he is around.