Arcane Guardians are bosses from Gemcraft Chapter 0, which defend the Gem of Eternity.

There are 2 ways of meeting an Arcane Guardian:

- Arcane Guardian levels

- Arcane Mode

There are 5 Arcane Guardian levels throughout the game, each of them starts off as a normal level, although the smaller infested buildings are replaced by Arcane locks, which will destroy your Wizard Tower if you don't throw a grade 3 gem bomb on them in time. After all the monsters are killed and all the Arcane locks are destroyed, the Guardian emerges from the main infested building, with a few Arcane Minions appearing from the side entrances. The Guardian has a huge armor level, which can be cut down by killing the minions, and it is immune to a certain gem effect (poison, slowing, freezing etc). The banishing cost for an Arcane Guardian increases by around 1000 mana each time it is banished. After beating an Arcane Guardian level for the first time, the player is award a Journey amulet.

Arcane Mode can be played after finishing any normal field, after reaching wizard level 64. The only differences with an Arcane Guardian level is that the Guardian does not come with any Arcane Minions and has no immunity to any gem effect.