Hatoful Boyfriend Wiki
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Heavenstrike Rivals was a free-to-play social tactical RPG for mobile devices published by Square Enix and UK-based developer Mediatonic Ltd. The game was shut down on May 1, 2018 after around 3 years of service. Before the game was shut down, it had several collaborations with Hatoful Boyfriend.

There was a total of 3 collaborations, each including around 2 characters from the original Hatoful Boyfriend game. The first collaboration included Shuu and Okosan as gacha characters and Ryouta as a unit drop character. The second collaboration included Anghel and Nageki as gacha characters with Kazuaki as the unit drop character. The third included Yuuya and Sakuya as gacha characters with no unit drop character.

The characters would be birds at first, but could be leveled up to become their gijinka version.