Grimshire 4 is a straightforward level.
Start by merging all the Prism Flower Sprouts in groups of 3, located to the upper left, the upper right, and lower middle.
Tap the Crimson Dragon Nests, and merge the eggs in groups of 5 to get as many dragons as possible.
In case your newly hatched dragons start attacking a Zomblin Cave, quickly tap the cave to free a Zomblin from it, but do not focus on taking out zomblin caves as soon as possible. You have enough dragons that you can take out anything that spawns before it can do damage to your camp.
Merge the grasses on the right-hand side in groups of 5, and merge the resulting Life Flower Sprouts in groups of five.
Locate the Blue Life Flowers hiding behind the Zomblin Caves, and merge them with the lone Blue Life Flower on the Super Dead Land in the top-most row.
If the Mushroom Cap in the lower right-hand corner has not been freed at this point, give it a Tiny Life Orb or two until it is freed. Use that one, along with the Mushroom Cap from the lower left corner, to free the Mushroom Cap on the Super Dead Land in the top-most row.
Merge your Spotted Mushrooms with the two on Super Dead Land in the middle of the map. Now harvest enough Tiny Life Orbs and Life Essences that you can make at least one Small Life Orb. Fire this one off in the middle of the cluster of Zomblin Caves, and you should now only have items on Super Dead Land. If there are still ordinary Dead Land anywhere, focus your efforts on clearing those before proceeding with the walkthrough.
Grab the Hero Mushrooms from the left side of the map and the one you got from merging Spotted Mushrooms, and free the one on Super Dead Land. Merge the Hills with the one on Super Dead Land, followed by using the Drake's Ridge you get from that on the two Super Dead Land ones. Now use that to heal the Edwin's Knoll.
You should have quite a few graves by now. Merge them all in groups of 5 where you can, and you should end up with 2 Lost Soul's Grave. Merge those with the Lost Soul's Grave on the bottom half of the map, allowing you to merge Life Essences and Heal Extenders to free the two Gaia Statues.
To finish the last Quest, grab the Fruit Tree Saplings from the upper right, upper left, and lower middle parts of the map, and merge them into a Young Fruit Tree. Place this one in the hole between the four Young Fruit Trees at the top of the map. Merge the Gaia Statues to complete the map.