I don't why people are complaining.... first of all he didn't use all of his op skills yet. and secondly we don't even know the demons level yet. he can be the same level as the MC.
OF COURSE A WORLD COMMANDER LEVEL DEVIL IS ONLY ON PAR WITH A NEW DEVIL WHILE HOLDONG S RANK SWORD THAT IS FROM A DEMON GOD NOT TO ME TION BLOODLINE SUPPRESSION FROM ANGEL BLOODLINE