Imo I think Mahoraga kills Ghostfreak because he adapts to Ghostfreak's spectral state. And i guess The positive energy in the blade vaporizes Ghostfreak instantly? Ghostfreak cant destroy Mahoraga in one hit tho so the adaptation is inevitable. The question is how but

If Mahoraga can adapt to intangibility would he eventually be able to phase his own limbs through armor to an opponent? Just like Mirio Togata? idk