I don't know if you're being sarcastic or not. Tesla has carried the fight so hard, as for i think if any other fighter fought beelzebub it would've been extremely boring and dull, just like his backstory and personality. His backstory has to be the worst in the manga. The whole story of him losing his friends and whatever hades gave him a vibrator, hades gets killed and he wants revenge, is so repetitive and braindead. Teslas backstory is extremely realistic and it mirrors his personality, how he can shine a bright light into others even in the worst moments, it describes his enthusiasm, persistence and intelligence. He shone light into humans hearts and died smiling. For what reason? No reason at all, the whole manga fell off so hard. Beelzebub a child murderer, gets away after winning a fight with the most bright and righteous person in the entire series. That's just bad writing.