The Mage is a Psionic Class that levels up like a normal soldier. It won't suit everyones game so keep that in mind.

Loadout:
Assault Rifle
Psi Amp

Squaddie:
Soulfire

Corporal:
Inspire
Fuse

Sergeant:
Protector (Gives Stasis *

Lieutenant:
Boon (Gives Resotre [Heal an ally for 6 health and fully restore their condition] & Solace)
Misery (Gives Malaise [Create a cloud of poison and misery at a location] & Soulsteal)

Captain:
Aegis (Gives Sustain & Fortress)
Voidmaster (Gives Voidrift & Schism)

Major:
Barrier (create a psionic shield around nearby allies granting them shielding)
Disable (Disable enemy weapons in a large AoE, can also stun them)

Colonel:
Teleport (Warp to any location within squadisght once per turn, free action)
Nulllance

GTS:
Hidden Potential (+25 psi offense)