Tap on Level 4 or 5 Graves for Grimm Seeds! Let them turn into Grimm Saplings then make 5 merges to maximize your Grimm Tree Growth!

Once you have a Young Grimm Tree or higher level, you can spread them out and just like Fruit Trees, they will spout items; most times you get Necromancer Grass but when you are lucky these magical trees can sprouts Grimm Seeds and even Grimm Chests!!!

You can also harvest Grimm Trees with your Dragons for Necromancer Grass or sometimes you can even get Grimm Chests!