Strength

From HammerWiki

Strength (S) is a stat to show how much muscle and brawn the character has. The stronger the individual, the more powerful their blows, and the more likely they are to cause damage to their opponents.

Each point of strength increases normal melee auto attacks by 0.1 damage per second, and special melee attacks by 0.2 damage per second.

Strength also makes your melee attacks more difficult to parry. (forumla : TBA)