The Tibia Mariners are the canon's gentlest, eeriest figures, pale boatmen who pole through fog-shrouded reaches of every great lake in the Lands Between, drifting upright in vessels barely larger than their bodies. Their craft is necromantic command. The Tibia's Summons sorcery, named for them, gives their function in two clauses : 'Sorcery of the servants of Death. Summons a group of Those Lost in Death. Three skeletons will appear some distance from the caster and attack foes before disappearing.' The flavour text adds the sentence that names what the Mariners are for : 'The dead have long been left to wander; what they need is leadership.'

Their boats are the canon's small image of an old psychopomp tradition, boatmen who, in the time before the Erdtree's grace claimed every funeral, ferried the dead across the underground rivers to the Helphen's lampwood. After the Erdtree's grace prevailed and Erdtree-burial replaced the older rite, the Mariners did not stop sailing, they simply took to the surface lakes (Liurnia, Summonwater, the Weeping Peninsula's coast) and continued offering leadership to the skeletal remnants who, refused Erdtree-burial, refused also to lie still. The skeletons that crawl from cracked stone tombs and reform after every defeat are the Mariners' standing crews.