To die by your side (is such an heavenly way to die) | Oneshot

Will was dying, he was dying in Mike arms and Mike couldn't do anything about it, it was supposed to be over, Will and El had made sure of it, but they all got separated, Mike was trying to find Will when he saw him stumbling in his direction, bleeding and trembling, and here he was, kneeling on the floor, holding his bleeding best friend in his arms.

Or, after the battle against Vecna Will is hurt and confess his love to Mike.