Bumbo the empty is not a good character. The main issue is the random spells every room. This makes fights moreso dice rolls than normal instead of the reasonable planning required in normal gameplay. You could have a good run going, but the second you get a tough room and garbage spells, you are out of luck... or are you?

This guide will provide a brief overview of RNG manipulation you can use in your runs. These are mainly aimed at Bumbo the Empty as a result of its extreme RNG build.

While I don't think it has to be mentioned, I will just in case.
Empty has random stats.
After starting a run look at your stats on the side and your health.
Not happy with the stat distribution? Simply go back to main menu and restart a run.

You have a good run and come across a hard room. You may even misplay and take a lot of damage. No worries! The game saves progress at the start of the room. If it's not going the way you like, you can simply go back to main menu and press continue. You will start back at the start of that room.

There is an interesting thing you can do using this tech. You get a trinket after the boss. Afterwards, you enter the shop rooms. If the trinket is bad or you get a bad roll on the wheel for example, you can simply do this reset. Both for the boss and the shop you will get set back to the beginning of the boss, but you will get a new selection of boss trinkets. The boss will stay the same due to the save being made after entering the room.

This is the part most of you are probably here for.
Using the roomresetting as described above, we can make the Empty change his spells! This can be done infinitely. You can simply keep resetting until you have good spells.

Interestingly enough, the board changes too BUT ONLY THE FIRST RESET.

Original room:




Reset 1:




Reset 2




As you can see, the board changes once and the spells will keep changing.
Also, I don't know why my screenshots are this bright.