Basically, while chipper and his bro where playing people were harpooning fish. so they were just playing tag when multiple harpoons where fired, piercing his brother

azul became doom slayer lol

i think the main difference in their reactions is azuL: had no choice and had to watch their friend get destroyed to oblivion. chipper: Was a complete accident and was avoidable. which would kinda tell them that a humans mistake can end lifes