Kyojuro Rengoku, from Demon Slayer. Currently dying with a severed arm of Akaza impaled through his stomach, he's going to die regardless of what happens now. He's happy though, as he was the only casualty in the entire 200 Person Mugen Train, meaning he succeeded in protecting everyone. The Flame Hashira, light-hearted and kind, caring, with an unbreakable smile on his face even when faced with certain death. He's in his last few moments, so make them count.