The shard is quiet

Twice a week a monster tide rises against the whole shard and stands for two days. It rolls in across those two days rather than arriving all at once — so it cannot be finished on the first morning — and once it crests it falls back on its own, which gives a shard that fought hard a way to finish it late. Any kingdom may throw an army at it — no range check, no war declaration, no target. It is the one thing in REALM that distance cannot keep you away from. Damage is tracked per kingdom, and when the tide falls the spoils are split by who did the work.