Guardian

The guardian is a defender that wants to reduce damage through high toughness and heavy armor. They get access to this heavy armor, though the drawbacks of it are noticeable too. Too much guard may be overkill and it may be better to stick to medium or light armor in some cases.

They control what the enemy can do by using Provoke and Threatening Aura. Provoke is a 1 turn Challenge for no AP cost, while threatening aura does cost 2 AP, but you automatically challenge everything around you. Challenge makes enemies provoke attacks of opportunity when they hit anybody except you, so you do need to keep in melee range of the enemies. Challenging Aura is especially good when you have other melee fighters that are squishy next to you. A berserker will greatly appreciate being hard to target.

To help with being a threat with your attacks of opportunity, the controlled opportunities key ability gives you a small bonus to them. Thanks to it, guardians are more free to ignore focus and power and focus on defensive stats.

Hold the line lets a guardian convert AP to RP at a good rate, at the cost of some mana. In a long fight, frequent use of this will let you keep your RP until you really need it.

Last Stand is an ability that should only be used when you know you're going to face many attacks during the upcoming round. The RP cost is heavy, but it can easily be RP efficient. You don't need to use mana on this for it to be worth it, but it's worth considering if you are likely to face a bunch of heavy attacks.