Tibia Mariners are minor field bosses found in Elden Ring. They are giant ghostly skeleton spirits that carry a long horn and rides a boat carried by ghostly water. They are able to summon undead minions, including skeleton spearman or giant spirit skeletons, in addition to attack the Tarnished (Elden Ring) with their horn or boat.
Defeating one will reward the player with a Deathroot quest item, in addition to various other weapons and spirit ashes. There are a total of 4 Tibia Mariners.