These are non-named, so they don't see invis or summon... but they have a LOT more hit points than the other normal chess mobs. They can be rooted/ snared, but I couldn't get root to stick for long. They are pure melee, and hit hard and fast. They dont summon. I haven't been able to get one below 32% yet without having to egress as a lvl 70 druid soloing with 7k mana. I keep going back for more though =p.