Is Romantic Killer Finished? Yes — Complete in 4 Volumes
Yes — Romantic Killer is complete. It ended in Japan with 4 volumes; the final volume came out in October 2022. The serialization ended on June 2, 2020.
Everything below reflects the Japanese edition — the source of truth that runs months or years ahead of English releases — computed from official publication records.
Volumes in Japan: 4 (latest: ロマンティック・キラー = ROMANTIC KILLER 4, 2022-10)
Next volume in Japan: not yet announced in Japan.
Status: Yes — Romantic Killer is complete. It ended in Japan with 4 volumes; the final volume came out in October 2022. The serialization ended on June 2, 2020.
Serialized since: 2019