Beware of spoilers if you don’t read the manga!
There will definitely be characters in Boku no Hero Academia that are going to die. We’ve already seen a bunch of deaths before, such as Sand Hero: Snatch, Sir Nighteye and Twice.
I’m not saying that they’re ALL dying but here’s my list of possible deaths:
Eraserhead: I think currently he's probably the most likely to die. His Quirk is probably the biggest counter to Shigaraki which makes him a threat to the enemy. Besides that, the doctor also had his eye on his Quirk in the past.
Gran Torino: „Leave it up to the pros", he said in the latest chapter. I think there’s a chance of him sacrificing himself to save one of the youngsters.
Hawks: He’s in a pretty dire condotion right now, badly wounded from fighting Dabi. Even if he recovers, I think the enemy wasn’t very happy with his betrayal which makes him a target as well. His death would probably lead to some character development for Tokoyami. I think Toga might be involved in Hawk’s death since he was there when Twice died and she's really angry about it.
Endeavor: As the #1 hero, Endeavor is probably another target the League of Villains wants to get rid of. His death would lead to character development for Todoroki. I could see Dabi killing Endeavor and Todoroki training to get revenge.
All Might: All Might is already weakened and lost his powers so I think it’s not that far fetched that he will die in the future. Besides that, Sir Nighteye previously used his Foresight on All Might and saw him die a gruesome death by a villain he will encounter in the future. It would also lead to some immense character development for Deku and possibly Bakugo. Bakugo might even blame himself for it since he still blames himself for All Might’s loss of powers.
Kyudai Garaki: That’s the doctor, for those who forgot his name. Idk but he already looks like he’s almost a corpse so I wouldn’t be surprised if he dies. But then again, we don't really know his Quirks limits.
All for One: He passed on his Quirk to Shigaraki so his role is pretty much done. I could see a scenario that involves him and All Might both dying.
Shigaraki Tomura: This is more of a death for later on in the manga. I can’t really see him spending the rest of his life in a prison cell. I think it’s that he’ll die after being defeated. And even if he becomes one of those „turn good shounen villains“ I doubt he’ll be forgiven for what he did.
These are just a few candidates that I think have a chance of dying. However, if Horikoshi decides to go for a darker turn of events, there will probably a lot more of the heroes dying. What do you think who will die in My Hero Academia?