Bloodthirst is a passive skill unlocked for the Barbarian at Level 10, which causes the Barbarian to gain life based on the amount of damage he deals, in a traditional leech-skill.
"Compassion is weakness. To press the advantage when an opponent calls for mercy is the way of true power." - Halaberd the Conqueror
Gain 10% of all damage done as Life.
Bloodthirst is a simple skill, if you were to look at it through the WarCraft II (or DotA) perspective, you would understand this skill as a 10% lifesteal. In Diablo II most skills didn't give life per hit, but there were health leeching prefixes on weapons, which could make any class gain health on hits. This skill is aimed to make the Barbarian less worried about health during battles, and should probably be taken as soon as possible if the player wishing to make tanking a breeze. It can be assumed that other skills which deal damage will also bring in health.
- Bash: The 200% damage of this skill will bring in a lot of health.
- Cleave: The health gained from attacking multiple monsters at once will be huge.
- Revenge: Activating Revenge within the time frame of Bloodthirst will bring in huge amounts of health, but you are limited to the small window of opportunity.
Passive skills have had a long and storied history. When Diablo III debuted at the WWI 2008, skill trees included passive skills, much like in Diablo II. In 2010, it was announced that passive skills had been renamed traits and separated out from active skills. At the July 2011 Press Event, Blizzard announced that passive skills were once again in the game, replacing the traits system.
Bloodthirst is unique in that it was an original passive skill and is once again a passive skill, but was never a trait. It is the same skill, but the stats may have been tweaked slightly.
For the July 2011 Press Event, it had a listed level as 1 (presumably so players could try it out from the beginning), but for the beta, it was a level 10 passive.