The walins split from his ancestor the plagueater. The walins' fins are deformed into something in the middle of fins and legs. It can't swim high and for long. Its tail is less made for swimming. It has lost his carnivore feeding and feeds on corpses only.
Their life cycle has changed and the mating period is 3 months long. The male walins makes a strange noise, which can be heard only by other walins's. That way he attracts females. After the mating is done the female digs a hole, with the transformed fins, and buries the eggs there. After that she goes searching for food, while the male protects the burrow. After the female returns, the male goes scavenging and the female protects the egg. The eggs hatch within 1–2 weeks.