Save you MP and SP in the Spirit Sanctuary, since the save spot at the beginning of this dungeon is the very only one. His head and body share the HP, but his staff has it's own HP. No special technique is recommended for this battle.
The Mage King has a weakness to Wind, Water and Earth based magic so ranged magic can take the boss down quickly. As Feena is not active during this battle, Liete may have to spend a lot of this battle healing the party.
- Mage King (Boss)