Black Ice weapons are uncommon but perfectly serviceable in combat. The Black Ice Greatsword, for example, outclasses the Hardened Steel version considerably, offering a 17-point damage increase and a 4% armor penetration bonus. It also beats out the Star Metal Greatsword, with an extra 4 points of damage and 5% armor penetration. Black Ice weapons are a considerable upgrade from Hardened Steel This comparison represents the improvement you should expect across the board with other Black Ice weapons. They should work perfectly fine for combat and have the bonus of decreasing your opponent's temperature when hit. It's quite the niche bonus but could help you get the edge in specific PvP encounters.