HP
From Fallen Sword Wiki
HP is one of the 5 attribute stats that determine the length of a battle.
The other attributes are Attack, Armor, Defense, and Damage.
HP allow a player to last longer in battle. The more HP a player has, the more damage that player can take. However, while training and leveling up, HP isn't important much because we want to make sure from levels 1 to 185 (est.) that we kill the monsters in one hit.
With the Buff Wither, a player can half the opponent's HP at the beginning of the battle.