Archon 2-Adept had four wizards on each side, alll monsters were summoned by spell, they were all new monsters and the powerpoints moved.
I have never gotten to play Archon 3.
About 10 years ago, Archon Ultra came out for the pc. The action takes place in 3d(including flying creatures being able to fly over ground pieces in battle). Every creature now has two powers instead of one. The graphics are updated.
Archon was also rereleased with updated graphics (and confusing cycling barriers) for the NES.