Resized to 66% of original (view original)

Artist's commentary
Anime trace
I think Sekibanki's is the only one who is harder to guess.
The
Answer
Is
Below:
1. Akuma no Riddle
2. Mikakunin de Shinkoukei
3. Futsuu no Joshikousei ga [Locodol] Yatte Mita
4. Arpeggio of Blue Steel - Ars Nova -