Seiji Asoh is the culprit of the Moonlight Sonata Murder Case from the manga and anime Case Closed. He is the son of the pianist Keiji Asoh. Going under the name Narumi Asai, he posted as a female doctor and return to Tsukikage Island to avenge his family.
What makes him magnificent?[]
- He has an understandable and tragic backstory of his family being killed by Isamu Kameyama, Hideo Kawashima, Tatsuji Kuroiwa, and Ken Nishimoto just because Seiji‘s father refuse to continue drug trade with him.
- This also makes him way less evil since Isamu Kameyama, Hideo Kawashima, Tatsuji Kuroiwa, and Ken Nishimoto all deserved their death at the hands of Seiji
- He is able to post as a female doctor on Tsukikage Island with a false identity for two years, which helps him to stay unsuspected for Hideo Kawashima’s death since Hideo is a muscular man, thus Seiji isn’t suspected at all.
- Played the tape of first part of Moonlight Sonata after Hideo’s death to mislead people into believing the sonata is related to the murder.
- By killing Hideo, Seiji is left as the only doctor on the island since it was under lockdown
- Seiji is able to create a false alibi after killing Tatsuji Kuroiwa by playing the tape of Moon,I hit Sonata backwards.
- Erased the evidence of the tape being backward when checking Tatsuji’s corpse.
- Wrote a convincing suicide note for Ken Nishimot after killing him and framed him as the murder of his victims.
- When exposed for his crime, Seiji decided to commit suicide due to being perfectly aware of himself stooping down to the level of his victims since he is now a murder too.
- Throw Conan out of the window to save him from the fire, even thanking him for exposing his crime.
- Is heavily implied to have been wishing his murder to be stopped by Kongoro
- His death left a heavy impact on Conan, making him always give the later murder culprits a chance to redeem instead of exposing them outright.
What makes him a baddie?[]
- Killed Isamu Kameyama, Hideo Kawashima, Tatsuji Kuroiwa, and Ken Nishimoto, even though they have it coming the show played it as Seiji being no better then them by being a serial killer.