A Yellow Dragon.

That's for the future, though. The other change that the tree father's existence brought to Legion in the present is that he can not only convert all types of energy into divinity, but he can store all types of energy too. This includes cosmic energy. 

This is a useful ability for them because Helios has a limit on the amount of cosmic energy he can store, which is based on his size. But the tree father has infinite storage, just like a Celestial's storage of divine energy and Aeternus's storage of Chaos energy. 

However, unlike a Celestial and Aeternus, his storage is not limited to divine energy or Chaos energy. So the tree father has become their bank for cosmic energy. It will help them prepare for when Helios is detached from the law matrix and becomes an Origin god. 

------