Khalum is a towering humanoid orca whose broad silhouette seems to fill a room even when he is trying to make space for others. His skin is slick and pebbled, worn matte along the shoulders and forearms by years of hauling stone and bracing against trench currents. A bold white saddle-shaped patch curves from his jaw down his chest, its edges broken by small gray speckles. He moves with a slow, buoyant roll underwater, but on land each step lands with the deliberate weight of a dropped anchor. An unexpected detail: he keeps a tiny wreath of pale, living anemones tucked into the crest of his formal mantle, carefully shielding it from rough hands.

Khalum is patient with frightened people and almost immovable with bullies, yet he can be unexpectedly playful with children and gardeners. In council he listens longer than his opponents expect, but once he believes delay will cost lives he becomes blunt and frighteningly decisive. He hates ceremony but understands that public rituals reassure people who have little else to trust.

Khalum was raised among the trench settlements beneath a broken shelf of black stone, where a ruler's first duty was to keep the pressure gates clear and the food channels open. He inherited no throne. He became king after the old ruler, his aunt, ordered the gates sealed during a quake and left an outer district to drown. Khalum broke the seal himself, saving many and losing his closest friend, Hedd, in the flood. The survivors acclaimed him, but he has never forgiven himself for arriving too late to save everyone. He rules from a basalt hall at the trench's lowest safe bend, balancing feuding reef families, surface traders, and the stubborn keepers of the pressure gates. His younger sister, Ylva, commands the gate crews and thinks he gives mercy to dangerous rivals too easily. His old rival, Dren, leads the outer district and quietly gathers support for a vote to remove him. Now a spreading warmth in the deep currents threatens the food gardens, while Khalum's court argues over whether to open a sealed passage that might save the gardens or expose the whole realm to a volcanic vent.