Treebeard

Treebeard, aka Fangorn, is the leader of the Ents in Lord of the Rings. His real name is not known, as one would need a large book just to write it down.

In canon
Treebeard rescues Meriadoc Brandybuck and Peregrin Took from the Orcs' skirmish with the Rohirrim, and minds them on Gandalf's orders. He then leads the assault on Isengard.

In badfic
Treebeard does not get as much badfic as, say, the Fellowship. However, he has been shipped with everyone from Legolas to Gollum.