Warning: The following contains spoilers for The Night Beyond the Tricornered Window, Episode 12, “Destiny”, now streaming on Crunchyroll.
It is actually quite easy to forget that The Night Beyond the Tricornered Window was marketed as a Boy’s Love anime, and it did start with some very strong innuendos about BL. But as the main plot kicked in around Episode 4, the often awkward BL aspects of the series naturally faded away and the series never seemed to look back. So when it came time to wrap up everything, the BL thread was one of those that felt a little out of place, and yet it somehow did work, thanks to some great performances.
Episode 11 ended with Mikado arriving at Hiyakawa’s mental barrier, and Hiyakawa attempted to run away because he didn't want Mikado to see him when he’s most vulnerable. He had also trapped himself within layers of curses, so it was still up to Hiyakawa to escape his own predicament. Hiyakawa felt that he had to hold onto his past hatred in order to fill the void in his heart and sustain his power, thus he was difficult to convince. Mukae talked to him for hours (time moves differently in the barrier) to no avail, so Mikado was the only person that could possibly get through to Hiyakawa.
Mikado finally understood why Hiyakawa needed his hatred, and started to feel real empathy towards him. If Hiyakawa chose hatred over him, he would have had to leave Hiyakawa, but if Hiyakawa truly believed that Mikado is his destiny, then he would be willing to choose Mikado instead. The fact that Mikado teared up here and basically begged Hiyakawa to choose him, means that he didn’t want to leave him either. This was a major development for Mikado, since he had been denying his feelings whenever anyone brought it up.
Voice actor Shimazaki Nobunaga delivered one of his best tearful performances but it wasn't too over the top, yet full of passion. It was possible to hear a sense of hope hiding underneath his cries of desperation, and it was incredibly affecting, especially coming from such a positive person as Mikado.
Hiyakawa admitted his fears and that he had always wanted to let Mikado know about his feelings, but since he couldn't understand them, he couldn't express them. Mikado comforted him by telling him that he won’t be afraid when they are together. This was a direct call back to the beginning of the series when Hiyakawa was able to dispel Mikado’s fear of ghosts. Hiyakawa chose Mikado and his curse naturally broke as a result. Even though this might not have been a conscious choice, Hiyakawa genuinely cared more about Mikado than any of his past trauma. Which was very important character development for him.
Viewers may note the subtle changes in the Hiyakawa’s performances hereafter. Voice actor Hatano Wataru did an excellent job of changing Hiyakawa’s vocal tone, so that he sounded slightly naïve and confused, but also less monotonous and gentler. There was finally sentimentality in the way he spoke and it was a great way to convey how Hiyakawa was slowly attempting to open up. The scene between Hiyakawa and Hanzawa was especially telling, Hiyakawa’s voice was at his most emotional here, even more so than when he cried. It is arguably one of the most touching moments in the whole episode, all because of the great performances on display.
There were a lot of flashbacks to earlier episodes to show the growth of both Mikado and Hiyakawa, but the flashbacks were quite clumsily handled compared to the vocal performances that could easily convey much deeper emotions than a few recycled scenes. This was perhaps the biggest flaw to this anime adaptation of The Night Beyond the Tricornered Window, the source material thrives on subtlety and implications, while the anime made most things too obvious and explicit. It did sometimes work to clarify things, but other times it felt a bit frustrating as audiences are perfectly capable of reading between the lines.
Though for audiences that wish for a full-on BL series, this final episode (and the whole series) might not be explicit enough, since there weren't any real love confessions or any physical intimacies except for some hand-holding. This is probably also because of the somewhat misleading marketing that sold the series primarily as a BL. Though the overall emotional payoff was still quite satisfying. Considering the wide array of themes covered in the series, this still stands out as one of the more sophisticated anime with BL themes out there.