Saddest Anime Death

Choose the saddest anime death. There are spoilers from:"Naruto/Naruto Shippuden, One Piece, Attack on Titan, Death Note, Your Lie in April, Gurren Lagann, Fullmetal Alchemist: Brotherhood, Hunter x Hunter, Code Geass: Lelouch of the Rebellion, Demon Slayer, Vinland Saga"