Ortan

Ortan is level 68 "field monster" added to Blessing Basin in level 70 patch (patch 80 in March 2019). Ortan also has World Boss icon before its name.

Ortan, along with two other monsters, Hazard and Cerrus have several special mechanics.
 * these bosses won’t display their remaining or maximum HP
 * only the player doing the last hit will get a reward box ('Ortan's Treasure Chest')
 * worldwide annoucement is displayed when boss respawns or is killed
 * bosses spawn 5 hours after they are killed.

Most players considered "last-hit" mechanic of these bosses have pretty much braindead. You can spend time fighting the boss, perhaps including opposing PVP-enabled raid for significant time, only to gain nothing. There also exists cheat mods that show the boss status helping proxy-users to pop up their broochs and boosts when boss nears zero HP, helping them to secure the kill.

This was changed in later patches. Participants now get "Ortan Raid Chest" or "Ortan Raid Silver Chest" with significant contribution. Who lands the last hit gets Golden chest. Last hit is still announced. Also random participant gets treasure award chest.

Unlike Hazard and Cerrus raids, Ortan raid silver boxes only drop scrolls for Skill Advancement (no relics, no halidoms).