The Guardian
Guardians lead the charge in the Templar's struggle. Wielding shields and swords, they thrive by drawing groups of Demons in close where they can then be punished en masse. Guardians are most effective when overwhelmed and surrounded and immobility can actually increase their effectiveness.

Guardians are probably the most versatile class in the game. While a typical Guardian build might be expected to utilize a sword and shield, players willing to try something a little different will find a surprisingly rewarding experience by instead wielding two Templar-specific guns (for example, check out the damage output of a Deadly Pepperbox or Novastorm).
Guardian Skill Advancement

Level 1: Aura of Renewal, Shield Bash (E1), Sword of Reckoning (G1)

Level 5: Anchor, Aura of Power, Challenge (C1), Shield of Faith (D1)

Level 10: Aura of Defense, Hamper (G2), Prayer of Healing (B1), Shield Turn (E2)

Level 15: Aura of Salvation, Aura of Thorns, Denounce (C2), Spiritual Strength

Level 20: Aura of Deflection (A1), Heavenly Condemnation (C3), Prayer of Retribution (B2), Shield Charge (E3, F1)

Level 25: Heaven's Arc, Provoke (C4), Shield Master (F2), Shield Wall (D2)

Level 30: Aura of Vengeance (A2), Grand Aura, Great Defender (B3), Stampede (E4)