In the Dawn War, the Rîninub (c.f. Rîni) fortress became a threat to Poseidon's undersea forces operating in Salzârrâk. He decided to put enormous resources into building a dam that would block the area's two great bays - Phedumarras and Nebezedel.
What shall we do about Poseidon's work on the dam?
We will let him continue to pour resources into it, perhaps he will finish by war's end.
Poseidon and his army of sea titans finished the dam a hundred years before war's end, but by then the areas around it were controlled by his enemies. He stubbornly continued to work on it, long after military operations shifted to other parts of the realm. The dam caused the two bays to lose half of their water, marooning boats and making Rîninub untenable for its defenders. After the wall was built and Rîninub reduced to rubble, Poseidon's army found itself surrounded in all directions by the angelic armies of the Nawirrûs Covenant. When he and his sea titan army failed to break-out of the cordon, he abandoned them. This decision would cost him later, because when he became a god, many of their descendants refused to pay him homage.
Much of the Sea Titan Wall is gone, with time, waves and currents having reduced it to half its former height and much of this just rubble.
On clear days, once can look into the depths of Phedumarras and Nebezedel and gape at the shadowy outline of the Sea Titan's great wall.
- Nirullu, elderaunt national historian - "Wonders of Izagunbar's Deeps"