In 4 everything from his jaw and below is fake. He's basically just a brain in a weird cyborg nanofiber body.
Yeah, he can still bleed out, that part is true, it's just, HF blade goes brrrr I'm pretty sure. Raiden clashes with DS even once, and he wins because his blade is going straight through it and into guts, unless he clashes from a bit away. But that'd still cut Guts range in half.
Tbh low key wanna call this a stomp, the only thing Guts has over his foe is some hax that well good and shit Raiden probably wishes he had (would've worked great on Vamp) won't really work here imo, and an, in theory, longer active ability (Raiden needs to get blood changed once in awhile, while Guts, in theory, can fight for days on end), but in practice that won't matter much here.