Abyssal Heir The Merman's Contract

Diver Julian swallows the abyssal pearl to save his gravely ill younger brother, awakening the sleeping merman tyrant Silas. Bound together by the prospect of offspring, the two are hunted by the regent Victor. Once the misunderstanding of their hostile bloodlines is cleared, they join forces to crush a usurpation plot, reaching a mutually-devoted ending in the deep sea.