Unidoom was one of the 8 phantom beast warriors. Unidoom has the spirit of the unicorn. He wielded a wrist-mounted blades that emit Rinzin Power. He was the main antagonist of the episode "One Last Second Chance". He is voiced by David Capstick.
Unidoom was revived along with the other 8 phantom beast warriors. Unidoom was sent with the brainwashed spirit rangers to cause trouble in the city. When master phant, master Finn and master swoop got saved, the 3 spirit rangers got unbrainwashed. Camille goes to fight RJ, but unidoom was destroyed by the 3 spirit rangers. Unidoom was revived for the final beast war but was destroyed by the 7 Pai Zhuq masters.