BLUE HEAVEN

The world’s largest luxury ship "Blue Heaven" saves a wrecked ship out at sea. At the captain’s command, the ship is searched, and 2 male survivors are rescued. On the ship, there are signs of horrible bloodshed. One of the rescued men, of unknown nationality, loses himself among the ship’s passengers and starts randomly slaughtering the patrons and staff. What is his motive?! (Source: Hawks & Omanga) Included one-shot: Route 69 — Description from AniList community (anilist.co).