A long time before Jeff was born, stalkers had been moving to a new area. They had to be hidden from human sight even though they could easily kill them. A cave entrance was used to travel different places. Mysterious but efficient the cave entrances were used for thousands of years. Every once in awhile a human would find one that had been left open and if they never entered they didn't have to die but when one was killed in a cave, that cave could no longer be used and had to be closed off. It wasn't often when a cave had been left open and not as often for a human to enter. Reapers usually opened cave entrances and Hunters killed the humans that entered. It wasn't long before human built up big city's and tall places. They remained hidden but it got harder for them to stay away from hand often. Killings happened more often than ever. As always Reapers opened them and as a Reaper a fourth class ranking they could also kill the humans. Some of the species had started growing feelings for things and were executed personally by the fifth ranking class, King. The King lives for at most a thousand years which is the longest out of any other class and they only ever die from age but when a King is let down from that ranking they go back to whatever class they were before. One King in particular was one that grew attached to things. This King might have been the greatest and strongest King ever but he grew attached to a human specifically. He watched this human grow up and one day she came to the woods while he was there and went in a cave entrance as he was there. But the thing that surprised him was that she wasn't scared if him. If anything she loved him. After years of them meeting she kept his secrets and he kept her secrets they eventually fell in love and since from rank two hunters up can turn into humans they had a baby and when they others sensed it he was exiled to the far lands. They never killed the girl since they assumed it wouldn't work half King rank and half human.
After a few months the baby had already developed she was expecting something but not this something. The baby had came out on its own, thankfully it wasn't painful but it's hands were solid black his eyes solid white with bright green. After a few months the child had calmed down and looked like a normal kid. She finally named him Jeff and went to the doctors for x-rays to see what he looked like. He was mostly solid something which was expected since they couldn't ever get a needle to stick in him. She paid them to keep quiet about it. She finally let him go to school and tried to forget about it. Eventually he could bleed again and turned into a mostly normal boy.
Jeff's mom had promised herself to never tell him unless the time came. She was worried that he might freak out over her and run off. She also feared him, with his immense power over her Jeff could easily kill her on accident. His dad was a King rank and a Reaper rank at the same time so of course she was scared. Jeff's mom also knew something no other figures did, that he the great King, Jeff's dad was coming back. He had told her that he would come back once Jeff reached a certain tipping point. He would train him to use the full extent of his power and show him how to take down the one who would try and kill the humans. Even though it might take time to get to Jeff he knew he would get to him even from the Farlands
Bonus
He felt the sense. He knew exactly what it was. His son had finally regained control over his power. He knew he had to reach him and soon because he felt the deadly threat of the one who would end the humans and also the sense that his son was in danger.
He busted out in a full speed run at a max of 300 mph. He dashed straight into the cave entrance he built years ago to escape the Farlands. He reached the entrance that he had hidden. He went through and appeared in the middle of Slender Woods. He could sense his son even better now. But also that his long lost wife is in danger along with a special girl that interested him. He started running for the girls because he knew his son would do just fine.
