Noah and Isaac could be siblings, Isaac was there at the police station with them and Finn gets reminded of Noah by being around Isaac maybe cause they're related and they look similar
In this list I try to collect all less romance manga and were is girl having good grips fight
Fighter girl
Underage fighter girl
Expression less
Swordship
Untouchable character
Psychology
Killing or thriller
Revenge
Justice
More powerful than man
Martial art
Boxing
Physically powerful
Reverse Harem
Kninght
Black and white
Colorful manga
Solo
Fantasy
Action
romance
Yuri
Comedy
Isekai
PART 1
https://www.mangago.me/home/mangalist/1145002/
and uhh the murderer could be Finn like split personality she did say she has "selective memory" she could be punishing herself for what happened to her dad by killings girls who look like her
It could be that Isaac is trying to lure out Noah by using Finn like how he talked about seeking justice and killing sinners at the cemetery
Young soo should have suffered more from consequences of his actions