Kii is grey with a white beard, wears a stone mask that shows his white eyes, and sits hunched over. He has a black tail similar to Opher's in shape.
Kii once ran a garden in Silent Woods, keeping countless trees under the bright moons. After the decay arrived, the garden withered away. Ori finds Kii standing next to his last tree, which he calls his last daughter, where he blames the Guardian Spirits for causing the tragedy. Kii asks Ori to find a gardener, which maybe could help restore the last tree, and gives them a Lifeless Branch. Tuley informs Ori that there's nothing he can do to save the dying tree the branch comes from. Moreover, the branch could cause other plants around to wither as well.
After bringing bad news to Kii, he gives Ori the Last Seed. Ori can bring it to Tuley, who plants the seed, thus getting access to Ancestral Light. The Gardener comments on it, saying that the seed is from an ancient tree, long before other inhabitants came to the forest. Once it's planted, the tree will stand long after. After planting the seed, Kii comes to the Wellspring Glades and can be found next to his tree. He says that the last seed may be the first tree.