"...So noisy." -Issei Hyoudou
To Mend A Broken Heart, is a crossover fanfiction, written in collaboration by Code-Emperor07 and Demons Anarchy of Pride. The series crosses Highschool DxD with the world of Tokyo Ghoul, set in a world where Issei becomes a Ghoul after being captured by Aogiri Tree. It is set at the end of the Tokyo Ghoul manga, and after the battle with Loki.
After a slight misunderstanding, Issei goes out on a walk to clear his head, not wanting to anger his master and his friends further, though he wonders what had he said that caused Rias to react the way she had. During the walk, Ddraig strikes up a conversation, knowing the reason why Issei phrases his words like they had, asking him if it was because of Raynare. Issei confirms this, having an emotional scar and bearing a fear that Rias will reject his feelings, or use him like the Fallen Angel had. Ddraig apologizes, thinking the reason why Issei had died was because of him, saying his partner wouldn't have become a Devil if he had managed to wake up sooner. Issei, however, tells him that it wouldn't have mattered, and that he would have been killed either way.
Shortly afterwards, he is confronted by two unknown individuals. Recognizing them as threats, Issei summons Boosted Gear, and attacks them. To his shock, his attack doesn't do any damage, and resorts to his Balance Breaker. At first, it appears to even the odds, but the enemy quickly turns things around and manages to tear off one of his arms. After this, he quickly dispatches Issei, and tells him he will be quite useful.
After he is rendered unable to fight, Rias and her peerage arrives, and out of rage, attacks the man. However, all of them are quickly defeated. To Rias and the others' absolute shock and anger, the second man seemingly eats Issei. Rias and Akeno attack the men together, though they are shown to be easily defeated.
Two years later, a unknown Ghoul bearing a red Bikaku and dragon-like wings appears, raising havoc amongs the wards and slaughtering countless Investigators. Having seen the level of power this Ghoul possesses, as well as his features, the CCG dubs him the Crimson Dragon, an SSS-Rated Ghoul.