Kurama first met Hiei a year before they met Yusuke. Hiei was chasing a demon at the time whom he thought had something to do with his twin sister's disappearance. Upon entering the human world, he comes across a powerful energy signature belonging to Kurama, who was still healing from his wounds when he was still the demon fox known as Youko.
Kurama's schoolmate, Kitajima Maya, was later taken by the very demon Hiei was pursuing. That was the first time the two of them worked together and had become friends ever since.
This is way too adorable for words. I really love these characters very much and am so glad there are still people who cosplay them! Great job!