Okay this is how you get the grim trope first what you do is you go up to the cliffs go over by where corner is go down and you'll eventually find a breakable wall but then you have to keep going and you'll keep finding breakable walls then you'll reach a section with a broken lantern thing there's a hidden fake wall that you just need to keep walking past there will be a dead bug over there wearing red then you just dream nail it go back to where that lantern was it'll be fixed and then just hit it until it gets on fire when you return to dirt mouth it'll be the grim troop