Bloodlust refers to a state where a character is fighting without any inhibitions, and cares about nothing other than defeating the enemy.
Bloodlusted characters fear nothing, and won't hesitate taking injures if it leads to a higher probability of winning a battle.
A bloodlusted character will not be victim to
Character-Induced Stupidity, and will be much more likely to speed blitz opponents (if doing so is within their powerset).
Some characters are naturally bloodlusted, and act this way in their own fictional continuity.