I'm using a single sprite for my game but It's gonna have a ton of NPCs, I was wondering if anyone could help figure out a way for the game to tell what NPC is what when they're are multiple of them in on the screen at once

I have a decent detection script that can tell if the player is near enough to an NPC without the need for sensing sprites which I am gonna use for dialogue
(It has a y cord sensor as well but I am too lazy to put that in, it's just connected by an “and” operator

Any way to tell the program which NPC it's talking to?

if <<<(x position) > ((X of NPC) + (100))> or <(x position) = ((X of NPC) - (100))>> then 
broadcast [ dialogue]

Make a sprite only variable that represents the ID of the NPC. Then replace the

broadcast [dialogue v]

with

broadcast (ID)

You'll need a bunch of broadcasts that are just a number however.

(If NPC clones are deleted, you'll need a separate way to store the ID)