Health is maxed at 100, and lowered in battles against other players. A successful hit lowers the opponents health by up to 40 points (with own health lowered by around 10), an unsuccessful attack will still damage the opponent (for around 10 points) while the player is injured by almost 20 health points. A player cannot attack if their health is 25 or below.
A successful attack will steal some of the opponent's unprotected coins. An opponent brought to zero health is killed, and can be looted for one collection item (which can be chosen among the opponent's treasures before dealing the final hit). Additionaly, a killed player can be robbed, which will transfer the remaining(?) unprotected coins to the winner, but also place the robber on the victim's guild's kill list - allowing every guild member to attack the robber, ignoring the usual lower level attack protection.
Health regenerates over time at a rate of 1 per 30 seconds. This can be increased manually by using red potions (available in 10%, 30%, 50%, and 100% varieties), using an elixier, or by leveling up.