Here I will tell you how to defeat Grimm, and in particular: how to dodge his blows, which build seems to me the most effective and just share the experience of passing this boss.
Learn His Attacks
So, the boss has only 6 types of attacks:
1. Makes a long lunge, after which it takes off into the air and disappears. After disappearing into the arena, six clots of flame fall. You need to make a jerk in the opposite direction from Grimm, and then turn in his direction and strike. (it’s worth being careful, because if you are too close to the boss he can cause you damage when he takes off) (sometimes it’s better not to strike, but just step aside to protect yourself from potential damage) Next he flies up and spews fire. In order not to take damage, you need to walk a little further from the place from where it took off. If you do everything right, you will hit him 1 blow and not take damage.
2. Appears on top of the arena and rushes at the character, then makes a long attack and disappears. In this case, the boss is followed by a fire trail, which can also cause damage. Here we just make a double jump and either move left / right, or make a jerk. On my own, I will add that some players managed to strike him down during this attack, but if you, like me, play from the keyboard, you will most likely be uncomfortable )
3. Spikes appear throughout the arena. The King of Nightmare himself does not appear on the battlefield during this attack, which does not allow him to be damaged. Just don't get under the spikes, lol.
4. He stops and calls from under his cloak four bats that fly along different paths, which makes it much harder to dodge. When you create bats over the hand of the King of Nightmare, a flame appears that can also cause damage. For this attack, you can manage to inflict Grimma 2-3 blows. To do this, you need to stay between the bats, that is, in the middle. We make a double jump in the direction of Grimm, and at that moment when we hear the sounds of the last flying mouse (according to the account it will be the 4th) we make a jerk, after which we beat.
5. Appears in the center of the arena and, levitating, swells and creates a large number of clots of flame. The attack is made by the King of a nightmare when he has 75/50/25% health. Probably the most difficult boss attack. Here you need to hide in a corner and dodge these balls. As you already know, the height of the jump depends on how long you hold the key. Keep this in mind when you go through this stage. It should be understood that you will not be able to immediately avoid his attacks. You will need about an hour or two to get used to it.