itch.io

You'd do it like this:

if(argument0 >= AMP_FIRST_ENEMY){
  return global.monster_data[amp_read_var(argument0,amp_MONID),mond_SPRITE_BATTLE]
}
else{
  return global.monster_data[amp_read_var(argument0,amp_MONID),mond_SPRITE_BACK]
}

The other thing I was vague about was where to add the back sprites. The init_monsters script has this place where we add an array of sprites for each monster:

Edit this and add a third "back" sprite after the map sprite. (Or before, if you prefer that, but then you'll need to make sure to adjust the changes I suggested for init_monster (without an "s" at the end) accordingly)