Amalgamia is a strange entity in FeverDev's games, who appears as a young woman. She speaks unusually, and has an odd awareness of situations, sometimes even fourth wall breaking.
Her appearance is very distinct and simple: Shoulder length brown hair, bright glowing purple eyes, no mouth, pitch black dress, two brown belts, a pouch strapped to her leg, and large dark boots.

To gain an understanding of Amalgamia, here are some games you can play featuring her:

Miracle, Amalgamia's origin story. It is a relaxed-paced game where you play as Amalgamia, before she becomes the entity she is in the other games.
Martyr's of Rome, Amalgamia is a main character with voice acting, takes place 1000 years after Miracle
Rusted Hearts: Crusade, this high action game takes place after Martyrs of Rome, and features voice acted Amalgamia as your side-kick.
Venerate, Amalgamia's action game, she has very few dialogue lines