The ED sequence summarizes the motivations of the protagonists and antagonists in the show. For the former, it's to right the wrongs they've experienced. For Keith, the death of his adopted sister Erika drove him to investigate the case long and hard. For Koku, it's to hunt down the culprits responsible for killing Dr. Heath and the other foster children in the institute. For the latter, they wish to usher in a new world order according to the prophecy and myths of Cremona. Or so it is, according to Gilbert.
Ray Chase being the voice of Keith and Heath Flick has an interesting connection between them. Heath's legacy is regret for being involved in the Cremonan Super-Soldier project, which was destroyed thanks to Gilbert's involvement. For Keith, Heath wishes to have him help Koku and take down the Big Bad responsible, while he tries to investigate Erika's death.
Gilbert had all the trademarks of a serial killer....except the arrogant need to taunt police with various clues, letters, and so forth. At least until the very end, but by that point he knew he was already uncovered anyway. Had Keith not already suspected him and been leading the rest of the team through somewhat subtle clues and discussions that would finally reveal Gilbert’s crimes, who knows how many more women would have been killed by him.
