Kallista is a Tiefling of striking oceanic hues. Her skin is a deep, bruised violet, and her hair is the color of kelp, often matted with dried salt. Her horns are unique, resembling branches of black coral that curve backwards over her skull. Most unnervingly, her eyes are solid, dark abyssal blue with no visible whites, looking like twin pools of deep sea water. She wears heavy sailor's leathers and a long, salt-stained coat.

Kallista is quiet and observant, often listening to voices that others cannot hear. She has a protective nature toward those who work the waves, feeling a deep kinship with common sailors and fishermen. She speaks in low, rhythmic tones that mimic the ebb and flow of the tide.

Kallista spent her youth as a deckhand on the 'Whisper's Edge', a merchant vessel known for skirting dangerous waters to avoid pirate tolls. That luck ran out when the Red Sails, a notorious pirate fleet, ambushed them during a gale. The ship was splintered by cannon fire, and Kallista found herself sinking into the freezing, lightless depths of the sea, her lungs burning for air. As her vision faded, a vast, cold consciousness touched her mind, offering a simple choice: serve or drown. She chose service. She awoke on the shore of her home village, the only survivor of the wreck. She was different, her mind opened to the whispers of the deep. When a group of survivors from a coastal raid needed guidance, she led them through a midnight storm to safety using her new, strange powers. The villagers hailed her as a hero, but Kallista knows she is merely an instrument of the vastness below. Now, she wanders the coast, seeking to protect the common folk while fulfilling the cryptic desires of the Dweller in the Deep. Her connection to her patron is not one of worship, but of a terrifying debt. She uses the power granted to her to hunt the pirates who destroyed her life, but every time she uses her magic, she hears the slow, crushing heartbeat of the ocean deep within her own chest. She has become a legend among the coastal towns, the Violet Sailor who can walk through storms and speak without words.