When Hisoka was 13-years-old, he went out one night to see the sakura trees near his home. Unfortunately, he witnessed Muraki killing an unknown woman. In order to keep Hisoka quiet, Muraki tortured Hisoka and cursed him to die a slow death that lasted 3 years. In the afterlife, Hisoka became a shinigami hoping to uncover the truth behind his untimely death.
This looks like the scene after Muraki’s curse on Hisoka. I really felt bad for this character, but I didn’t realize “that” happened to him until much later. In any case, thanks to Miaka for sending this in!
Source: ゆぅき on Cosplayers’ Archive