After escaping Melascula's spell you were flowing with demon energy as the other sins looked at you in a shocked state and are surprised that you escape. After you've fully entered assault mode Escanor stepped up to fight you

Escanor: Merlin stand back I'm going to have a fun time dealing with this demon...

Merlin: Escanor you can't! This is his pre-demon state. The state that considered him the hero of the demon realm 3 000 years ago.

Ban: Hey Captain is it really you?

Diane: This Magical power.... it's powerful.

Gowther: His magical power in this state is 142 000.

Elizabeth: Merlin please we have to help him!

Hawk: He's too overpowered....

Creates a perfect cube around Escanor and You

Melascula: You can't stop him! He's back! The true throne to the demon race!