Ungreez

Was implemented in the Summer Update 2008. Part of the Demon Hunter Outfits quest, you need to kill Ungreez to gain all experience for your first addon. Ungreez is Stronger than a Demon and its tolerance to attacks are the reason for it. You can use a Blessed Wooden Stake on Ungreez once slain to get a Demon Dust.

This monster fights until the death, with its strong beam attack you should stay diagonal. ¨He walks through Energy and Poison Fields, although it is not immune to them.

Just like a normal Demon, however, does not summon Fire Elementals.
Knights try to use Exori Gran. It is strongly advised for knights under level 100 to have a blocker or a healer, since he heals often.
Mages can easily solo them from level 45 and up, run from teleport to teleport and using Magic Shield and Sudden death runes to speed up the killing a little. You can also run it in the room, since the room is quite big. Ice spells/runes will also work. If you have blocker you don't need go outside the teleport to charge mana.
Paladins should run or kill with a blocker while using Assassin Stars and Exori San. Paladins can kill Ungreez at lower levels with a blocker, using Enchanted Spear and exori san, be careful with great fireballs.