Several minutes after Lucifer left the main underworld portal, Xugguth was busy organizing the defense. He didn't think anyone was foolish enough to come to attack them, but he intended to form the best defensive perimeter possible. He wanted to impress Lucifer upon his Lord's return.
If he managed to do that, Lucifer might probably give him one small piece of this upperworld. He had been sulking for losing the chance to join the conquest forces. He had to stay behind for guard duty instead. There was no chance to gain merit if no one came to attack, so his chance to accomplish anything was close to zero. This also meant his chance to gain any territory in the upperworld was just a pipe dream.
He was a level 94 eternal grade. Even in the underworld, there were not many demons as strong as him. However, this was also the reason he was chosen for the guard duty. They needed one of the top demons to secure the main underworld portal.