Hello, the author here.
I see many comments in the last two chapters is complaining about Zelretch, and I should kill him.
Let me tell you something, Did you know that Kaleidoscope is World Breaking Power in Worm CYOA?
Did you know why?
Because the user of Kaleidoscope is practically immortal, Kaleidoscope not just ability to Travel around the world.
Kaleidoscope power in worm CYOA
Kaleidoscope: You are attuned to not only the fabric of space and time, but the very essence of the multiverse itself, All-World, Timelines, and possibilities are now within reach of your new sense, and you find yourself able to manipulate them to your will and even travel between them. What you can accomplish with this is limited only to your imagination and experience — drawing in alternate Version of people to fight under your control, copying power from alternate selves or fictional characters, fixing a destroyed neighbourhood by overlapping a pristine on it.
These and any imaginable manipulation time and space (Time Travel included) are within your reach, and it isn't limited to worm verse. The entire infinity is at your fingertip.
Basically, he can search for power that able to kill Yu instantly and be done with it, and he uses his free time to Prank and causes chaos everywhere is because he already knows what the future looks like; he wants to create something that he cants see with his power.
And you know that something disturbing? Zelretch able to Copy Yu power if he wants to because Yu technically is Fiction Character so he can Copy all his power Set.
Then lastly if Yu were able to 'Kill' Zelrecth, he travels back in time or Informs all of alternate Version of himself that already reach root and gain Kaleidoscope to Destroy Yu and all his Alternate Version before he even reaches adulthood.
Think before speak, dude. Sometimes there is another powerful Character that able to kill the MC