These themes are meant to enhance the combat roles of a character. As with all themes, any character can take any theme.
This theme goes well with backgrounds that give you armor proficiency, and classes that enhance your melee attacks.
On your turn, choose an enemy adjacent to you to mark. The enemy is marked until the end of your next turn. A marked enemy takes a -2 penalty to hit any creature other than you.
Once per round, when an enemy that you have marked makes an attack that doesn't include you, you can make a melee attack against them.
You can mark one more enemy.
Your mark can affect any enemy within 25 feet.
You can use a ranged attack instead of a melee attack when you use Retribution.
You can use Retribution twice per round.
This theme is good with classes that use Dexterity and enhance your melee attacks.
When you have combat advantage, your attacks deal 3 extra damage to the target.
You can use your action to gain combat advantage against one enemy within 25 feet.
You have combat advantage against any enemy that has not yet acted.
One enemy within 25 squares of you is your quarry. Until that enemy dies, it takes 3 extra damage from each attack you make.
When attacking you quarry, you can roll the attack twice, and take the higher of the two attack rolls.
You deal an additional 2 points of damage when you have advantage (total 5).
On you turn, you recharge an ally's second wind.
When you recharge an ally's second wind, you can activate it for them, giving them its benefits on your turn.
When you recharge an ally's second wind, you can move them into or out of melee.
Once per short rest, you may turn a hit on an ally into a miss.
Once per short rest, you may turn a failed saving throw into a success.
Once per short rest, you may turn a missed attack into a hit.