Complex sentence: The next night, they enter the tower again and defeat Mangu's thugs and while Mangu is attacking them himself, they are shielded by the unknown creatures and are brought to an unknown place.
Split into simpler sentences: The next night, they enter the tower again and defeat Mangu's thugs and while Mangu is attacking them. They are rescued and shielded by the unknown creatures and are brought to an unknown place.