>>280575488
Raiden did pretty well in his little tussle with Prisoner without his battle suit, and while Prisoner was obviously holding back and fighting defensively to protect the Puri Puri Prison Partners, I think Raiden is at least more powerful than Prisoner was during his fight against the Deep Sea King.
It's just that Prisoner got so much stronger afterwards that Raiden doesn't look all that impressive now; he'd need to grow a lot more himself before he can truly match up to Prisoner, but he's at least genuinely S-class material.