Naruto โ Going off OBD to scale both, Akainu is small continent level whereas Hashirama is County+ Level. So Hashirama is the best Akainu can hope for, probably. Beyond him you get the lower end God Tiers who are insanely above Hashirama. VS wiki (different source, but I couldn't find one for OBD. Probably similar results anyway) has Obito once he becomes the Juubi Jinchuuriki at Multi-Continental level and he's one of the weakest God Tiers.
Bleach โ I'm shit at power scaling Bleach lol. Wish I knew the answer to this as well. OBD has most Captain class characters at massively hypersonic, I'm seeing, and Akainu at Relatvistic. So, he speed blitzes all of them. Their DC also seems to cap at city level.
Dragon Ball โ Late Dragon Ball Goku or Piccolo. Demon King Piccolo could demolish cities (and assumingly larger areas) with ease, and both Piccolo and Goku are much stronger than that version of D. King Piccolo. Once you get into Z, however, it's pretty one sided. Piccolo shortly after the Raditz fight destroys the moon lol. Krillin with his power suppressed โ 981, 1220, or 1083 as the manga doesn't clarify who's power is who โ is already superior to that Piccolo. Hell, he takes on multiple Saibamen whose power are described as being equal to Raditz.
So, once we enter Z properly, Akainu gets sent to the moon with that Carrot guy.
MHA โ He kills the whole verse.
Fairy Tail โ I shamefully read this whole series but I find PLs in it to be wonky, and at the end of its run I didn't enjoy the series. I read it only due to the fact I poured like a year of my time into it. Akainu probably kills everyone but Acgnolia. He seemed tough.