They won't. Season 5 is going to adapt volumes 16 to 18, and nobody dies in them.

As for anywhere in the future, Oomori is just not the type to kill characters, much less important ones. He has only ever killed one recurring character, it was a secondary one, and it was in a spin off to top it off. We are 19 volumes into the main serie. If he was actually willing to have a remotely relevant good guy die, he would have already done so.

They seem come out of every event relatively unscathed. Like no permanent damage.

@Morgan Halfyard

Season 5 will be base from Volume 16-18 and no one died. Oomori is not like that, unlike the author of JJK... He's been killing a lot of those important characters lately.