Review Detail of Roktah in Highschool dxd : Yasaka is my wife

He can transform into an angel to fight devil's or transform into a devil to fight angels, since high level devil's have light resistance. Devil's also have imagination magic. He could also have 2 separate peerages, an angel one and devil one. That's if he can get the items to make the peerages

That's without mentioning that with balance breaker he could balance holy and demonic energy like kiba and bedome a holy devil or demonic angel, which was shown to be op in canon

you think any chump can just recreate the evil piece or brave saint system? the reason i say its useless is because sure he can take advantage of their weakness but its not like thats anything new. the angels and devils have faught one another for millenia, at first their might be an element of surprise by it but once his sacred gear is known its the same old stuff.

cool, but its still just a transformation that he needs to activate by pressing a button, nothing prevents him from being killed without warning before he can turn into a devil an angel or whatever nephilim you mentioned. not to mention the limit on his lifesan as a human will very quickly become an issue, his skills both as devil and angel will need to be trained as they surely don't come natural to him afterall he is merely transforming into one of their kind he will not have the same intuitive skill

Sacred gear on only limited by imagination and strength of will. Once he gets good at it he won't need to hit the button. Also, the sacred gear is made by god, the same person that made angels and devil's. That would be like saying devil's that used to be human don't have devil instincts. He literally turns into them, he isn't going to have any instinct problems. He still has a second sacred gear that makes him stronger as a human. Anyone that can one shot him before he transforms is already out of his league

I didn't say recreate, I said get them. Nothing is stopping him from befriending rias and getting his own pieces by marrying her. Not to mention that the brave saint system was made with the cooperation of ajuka and the angels. He can just get them

the ability is still useless tbh it wont help much

Humans are limited in strength in dxd. Cao cao with the strongest sacred gear designed specifically to counter all supernatural beings, powered by the will of the biblical god, maxed out at juggernaut drive Vali before the author wrote him off as an antagonist because he couldn't keep up. That's him pushing the true Longinus further than anyone else before him. The mc can bypass his human limits and at the same time use his other attack sacred gear with holy/demonic elements. Keep in mind that the seraph are only as strong as they are because they can use holy imbued elements

A big part of the plot is humans being weak. That was cao caos whole reason for trying to exterminate the supernatural. Vasco would have instantly become one of the strongest angels if he didn't choose to die a human. Do you not read?

I do think YOU are not able to read what i did write devils and angels as a race as humans are all weak the ability to switch just to a race and nothing else JUST TO SWITCH is useless