No One

The invaders didn't understand what happened. The sixth level immortal included.

They knew that one of their opponents said something after the sixth level immortal was sent flying back by what seemed some kind of ghost, but an instant after that, all the opponents were gone.

Astel had still looked somewhat transparent when he appeared, and no one could remember him, so their best guess was some kind of ghostly double technique or something like that.

"They should be hidden nearby! Look for them!"

The sixth level immortal didn't believe that they had died since they hadn't attacked them after she was sent flying backward. She had seen the effects of Gerken's cloak, so she believed that they used a similar method to hide themselves. After all, she just knew of the stealth effect. She didn't know that it was provoked only thanks to the effects of Gerken's cloak.