Maneuvers are Guardian specific self buffs gained at level 20.

The Guardian takes less damage in battle, but also deals less damage.
(-10% Damage, +5% Spell resist to all schools, +10% Stun and Fear resist)
The Guardian's attacks appear more threatening, although they actually inflict less damage than normal.
(-5% Damage, +10% Hate)
The Guardian increases the damage inflicted by their attacks, but lowers their maximum health.
(+5% Damage, -9.25% Max Health approx)