Ent
Ents, Shepherds of the Trees, created at the prayer of Yavanna the Vala, are certainly very ancient, possibly even predating the Elves. They are a race of giant, tree-like people whose purpose was to protect the forests of Middle-earth. By the end of the Third Age, the great forests had dwindled, and so had the Ents, but they were still to be found in Fangorn Forest.
In MUME, Ents are plant-type mobiles. Just like in the books, they are found within Fangorn. While not normally aggressive towards white-side players, they will be angered if you attack them, or if they see you casting fire or lightning spells. In that case, you will be given several warnings to leave the forest, and if you fail to do so, all Ents in Fangorn will become hostile to you.
This is something you probably want to avoid, as Ents are tough opponents to face. They are at least level 18, very hard to kill through their tough bark, they can bash and some of them track, and they damage your weapon and shield if you parry any of their attacks.