Only saving the Lesser Rebis was not enough since the forest was not enough to contain its power, so it would need to be killed by Zelhart even if the elders managed to save the Lesser Rebis from dying.
A total reversion of its life form was needed, something that not even Hulum Ying or the God of Thunder could dream about doing, as surgery at the molecular level. Only one person in the entire world could do something like this, and it is facing Zelhart now.
Someone that built all life forms and could shape the way she wants.
Zelhart already wished to see Nature once again and was ready to do anything for Yuriel and Isaac. But it was strange to hear her asking for something.
"Anything, but please, fix what was done to them."
And so she approached the Lesser Rebis on the cage, opening to give freedom to the Lesser Rebis that was not aggressive at all.