Don’t have them die of old age after a long, fulfilling life. Many people don’t even think of this as sad (note that this can still work if you have enough of the other factors).
Leave one of their major goals unfinished. The more enthusiastic they are about completing the goal, the sadder.
Give them strong relationships with other characters.
Make them fight against whatever is causing their death. Their ultimate loss is sadder if they struggle.
Kill them in the middle of their character arc.
Don’t describe their funeral in detail. Maybe it’s just me, but I find that long descriptions of funerals kill the sadness.
I’m not actually big on major character deaths, because they tend to upset me, but this is a good reference for anyone with a heart of stone.
in most routes, sans will quietly endure whatever suffering is forced upon him. he can live through the callous murder of his brother, the slaughtering of his friends and peers, and yet he’ll do nothing to frisk but berate them. instead of disposing the human the instant they begin harming others, sans watches and waits, appearing near the end of frisk’s journey only to launch his emotional appeals. he attempts to guilt trip frisk, and by extension, the player, rather than get his own hands dirty.
there is only one exception: the genocide route. only when the situation has become the most dire does sans spring into action to do what’s right. what makes the genocide route so different from an especially violent neutral route? why does sans only wait until the genocide route to fight? continue reading for the reasons.
Dragon Blog 