Here is the full list of all 15 Xanadu Next achievements.
Attained all other achievements.
Found and maxed out all Guardians.
Found and translated all tabulae and memoirs.
Defeated Dvorak.
Conquered another dimension.
Innately learned all skills and acquired all levels of all spells.
Reached max rank.
Defeated Galsis.
Defeated Lorelei.
Defeated Ascomoid.
Defeated Evilwurm.
Defeated Scoltula.
Defeated Berilard.
Barely made it back to shore after almost drowning.
Mapped 100% of the game.