This probably doesn't qualify as fanfiction. Maybe this is somebody else's cup of tea, but personally I don't like when an author spends more time vicariously talking trash about the original characters through the mouth of their cookie cutter Gary stu, than bothering to get their terminology and lore right.
The main character here is just a deuche, a low effort, and poorly written one, but overall just a trashy personality. No nuance there. Then, when the mc contracts the nightmare spell, and enters his first nightmare the author keeps calling him a sleeper and saying he's in the dream realm. The guy enters and just automatically gets three free memories. Not, he had to kill so much as a baby squirrel, no, he just had them like taking the role of a foot soldier would just give him that. Forget that the ancient warriors of the dream realm, which the nightmares are based on the history of, didn't have memories... Followed by more pointless jabs at sunny and his first nightmare just to make this bland, boring warrior character that's just completely in love with himself.
Just why? What was the point? Work on the character writing because what you've written doesn't qualify to be called it's own character, rather it's just a low effort puppet for the authors biases on the original work, which this piece reads like they barely skimmed it.