Somehow 100%'d all 3 demons, this was fun!
Got to say tho, it is mostly memorization. I just wrote down what runes did what for each demon/round. I still found it fun but I think others might find it annoying.
Also, it seems Trerzothar's 3rd phase has a bit of weird hit detection. I found myself constantly saying "I should have hit that!" during that part which got tiring fast. Could just be a skill issue tho.
I like the premise, can't wait to see the 4th demon!