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