Mystery Jr.

MysteryHood and Kurahi were scavenging in the Metaverse, which led to them find an ancient artifact.
Like any responsible adult they immediatly touched it.
The magical artifact took a portion of their life force and chakra and fused them.
It created a tiny creature which looked exactly like MysteryHood. 
MysteryHood and Kurahi decided to adopt the small creature, making them both the fathers of the creature.

When they asked the Celestial Metaverse Gods why the kid looked like MysteryHood,
They said that the creature had to take the form of at least something. The closest living creatures were MysteryHood and Kurahi, so it was just a 50/50 chance on who it would choose.
MysteryHood just happened to be chosen.

Fittingly, he was named Mystery Jr.