Gray is no doubt strong.He completely fodderised Invel.This is not a matter of joke.Pretty big feat.Partial end isn't stronger than gray they were equals all the time they fought..c'mon now.
But as he had Slaying advantage he had a huge advantage against Partial END.If they were really same then Partial END would have even fared worse than Mard.And we have few evidences which prove atleast in powerlevel Partial END is above Demonised Gray.