The Immortal Treant abuses the fact that treant form is considered an animal and thus able to be buffed with Greater Magic Fang and Nature's Avatar through the feat Natural Spell. It also abuses the +shield ac modifier on a magic shield being melded into the tree form while removing the shield allowing full wisdom/int ac gains from monk/duelist. * * * NOTE*** Nature's Avatar no longer works on yourself when shifted into tree form. * ALSO NOTE Greater Magic Fang no longer works on yourself when shifted into tree form aswell, so this build is now out of date