Purpose: The tree, Ail and Ann are aliens but were forced to leave their planet. The tree used to be the Tree of Life for their planet but became the Doom Tree as it weakened. Ail and Ann depended on this tree for their lives and stole energy for the Tree without knowing that their actions were in fact killing it.

Main villains:

Ail or Alan in the DiC version
Ann or Anne in the DiC version

Underlings: Various cardian

Defeated: Episode 59

The aliens realise they are hurting the tree and instead Sailor Moon heals it allowing the aliens to start a new life.