Capítulo 1345: A Daring Plan.

The invasion is nothing personal or for revenge. Kilorita did steal the child of the plane from Legion-7, but that's not the reason why they will be invaded. Legion-7 hid a lot of the wealth he took from the dead gods in the plane. Someone has to go and get it. Plus there's more wealth that the Celestials are hoarding. So the invasion is strictly business.

It may have a side of pleasure but what was strictly business was when the tree father made a demigod of order and killed the girl for her core so that Legion-5 could acquire the divine ability of Order. It was also business when Legion-5 killed several great gods to enhance that divine core to the level of a great god. 

Many people have sacrificed a lot for Legion-5's plan including the clones of the Legion. Aeternus even gave him one of his crowns and helped him get a Celestial godhood of order. This is just to see if his plan will work. If it works then he will need even more investment.