What is the Spirit Sanctuary ?

Spirit Sanctuary is where the Embodied One is allowed to enter.

The Spirits have deemed Justin fit to enter, so The Gate of Spirits opened in Jil Padon.

Dungeon Map

Spirit Sanctuary (1)

Spirit Sanctuary (1) map

Legends: S - Save Point, V - DungeonScope

* The north-east area highlighted by the red dotted line is like a maze (refer to the Walkthrough section below).

Spirit Sanctuary (Room of Truth)

Spirit Sanctuary (Room of Truth) map

Data

Treasures

-ItemNote
1Revival Stone
2Force KnifeKnife: ATK+65, ups attack range, [WOW!]
3Spirit ShoesShoes: DEF+30, MOVE+50
4All-Around Fruit
5Fruit of Magic
6Gauntlets of LightShield: DEF+25, +1 all magic resistance
7Seed of Life
8Fruit of Moves
9Spirit SwordSword: ATK+70, restores SP in attacks

Enemies

EnemyHPEXPGoldDrop
Guardian550179245-
Critter325231157-
Stingray392182182-
Mage King (Body)389211353200-
Mage King (Head)11353200-
Mage King (Wand)234611353200-

Spirit Sanctuary Walkthrough

Upon arriving the Spirit Sanctuary through the Gate of the Spirits, go north past the Save Point. New paths appear east-ward and west-ward from where Save Point is.
If you go east you will eventually arrive at your destination. If you go west, you can pick up "Revival Stone (1)" and "Force Knife (2)".

New paths:
You may find yourself at a dead-end and nowhere else to go, but if you retrace you will find a new path that lead elsewhere.

Once you reach the DungeonScope, you have to choose from two routes in which only one is correct. Choose "Pink → Green → Blue" as shown below.
At the center of the Spirit Sanctuary, you will have to fight the boss "Mage King".

Spirit Sanctuary DungeonScope surrounding area

After defeating the boss, step onto the pedestal and you will be transported to the Room of Truth.
You will receive "Spirit Sword" at the center of the Room of Truth.

Then you will leave the Spirit Sanctuary to find yourself at the entrance of J Base.

Boss Battle

Mage King

Moves/SpellsEffect
Mage King (Body)
HowlnadoWind damage (all)
VanishRemoves buffs/debuffs (all)
Mage King (Head)
Divide BeamDamage (straight line)
Wand
GadZap!Lightning damage (1)

The boss is "Mage King" with a "Wand" in his hand. Mage King consists of two parts: the body and the head (they share HP of 3892).
You can win the battle by defeating the Mage King only, so ignore the Wand.

Divide Beam is a range attack (in straight line), so in theory your party members should spread apart. However the boss' HP is not that high, it would be quicker to just keep on attacking rather than wasting your time to evade.