DGray-Man & Katekyo Hitman Reborn

Skull and Allen were friends in the circus. Skull, going by the name of Cherep at the time, was an errand boy at the circus. His adoptive mother was the fortune teller there. Upon meeting Red (young Allen), Cherep takes him under his wing and adopts him as his little brother. Cherep teaches him everything he needs to know in the life of a traveling circus. Along with that, he also teaches him kindness and general people skills.

A few years pass. Their circus travels along, gathering new people and getting bigger by the day. Cherep has taken on the stage name Skull DeMort due to his death defying stunts on a motorcycle. Red was given the name Allen after he was adopted by Skull's mom. You can come up with your own stage name for him if you want to. I was thinking of something with "Red" in it, as a kind of momento for his past. I was kind of debating on "Red Angel" and having Allen be an acrobat.

Then the plot kicks in. Allen walks in on someone in the middle of making a deal with the Millenium Earl. The Akuma Skelton attacks him and gives him his cursed eye before his innocence activates and kills the akuma. Allen falls unconscious and is taken by Cross.

Its years later before Skull and Allen meet again. Skull is with the strongest Seven (future Arcobaleno) and Allen is with the Black Order. I have it where both are on separate missions but the location is in the same building and naturally the two teams cross paths. The only reason an all out brawl doesn't happen is because Skull and Allen recognize each other. After this I don't have any other ideas (mostly cause this an old idea of mine and I forgot everything after this point lol) so however you want the reunion to go is up to your brain. Good luck!

It's pretty rare when I don't have a fandom that I'm like "how can I make a crossover with KHR". Skull is my favorite character and I love the DGM stories where Allen is de-aged into Red or they explore more about Allen's past in the circus. A popular headcanon of mine is Skull being apart of a circus before being invited to the Arcobaleno, so naturally my brain is like "2 circus kids? Make them be friends" and who am I to say no?