can you go to prison for kiling someone in the ring?

No, in the over 100 fatalities directly from a boxing match never has any boxer even been charged, never mind gone to prison.

If you were cheating when you killed some one, like using plaster in your fist, then you will go to prison.

If you killed them but you did not cheat, then you will not go to jail. The other boxers physician, the ring doctor or the ref. will be blamed, and maybe even the organization that gave the boxer a boxing license.

that depends,

there would be a police investigation and if it was deliberate yes you could.

regardless of the out come of the investigation you are also could be found financially liable in a civil suit as well,

those waivers you guys sign would be ripped to pieces by any half witted lawyer, dont count on them saving you in court

No I don't think so, I think the Ref might get in trouble for not stopping it though.