You see Troll Legionnaire
"Attack!"; "Graaaaar!"
Notes
New creature in the summer update 2009. They can be found in an area accessible during making Royal Rescue Quest. Drops quite high amount of gold for such a monster, so hunting these might be profitable.
Abilities
Melee (0-40), Throwing Star (0-130), Invisibility (often), Self-Healing (fast).
Damage Taken From Elements
Physical 
Death 
Holy 
Ice 
Fire
Energy
Earth
Location
Old Beregar mines. In group with Furious Trolls almost all the time.
Strategy
They will most likely be invisible all the time, as they re-cast invisibility and keep distance before the effect wears off (like Warlocks), therefore shoot area runes like Great Fireball or use spells like Divine Caldera. Alternatively, change floors for a while until they become visible again.