Author's Note: Heyo, here's a new crossover fanfiction that no one asked for. I made this because I had read a really good story named Trolls vs. Wizards by Reuben_Aloway, and since I can't find a story like Reuben_Aloway's, I decided to do one my own. But couple of things to clarify.-This is set after season 3 because I love troll Jim and because the situations will be much more interesting.-This story will take place in the Order of the Phoenix and nothing else since this is a much shorter story than Guardians of Arcadia.-Chapter may be a bit spotty since Guardians of Arcadia is sort of my main story.That's all I got, next chapter with be longer don't worry. Feel free to comment on what you think aboht this of this since it can give me a boost of motivation.

James woke up in his room at 6:00 AM, he stretched his arms out and yawn quietly. James' energy kicked in as he realized it was his birthday. He smiled with excitement and hopped out of his bed; Jim left his room and ran towards the hallway. The boy opened the door to his parents' bedroom and saw mother sleeping; as he quietly closed the door James heard some noises coming from downstairs. James carefully walked downstairs and saw what looked to be his father, frantically moving back and forth and he was searching for something in the kitchen.

"Dad?" James asked as he tilted his head.

His father glanced at James, looking quite pale and very nervous. "James, your up early."

"It's also my birthday dad." James stated, rocking his hands back to back.

"Well of course it is, why would ever forget my son birthday." His father commented as he smiled.

He approached his son and hugged him tightly, he took one deep breath to avoid crying and ruffled Jim's hair. "Can I wake up mom now." James asked.

The boy saw his father flinch while looking away from him. "Maybe we should let her rest for a bit, in the meantime why don't you open the present I gave you." The father suggested, Jim eyes lit up and started bouncing up and down.

"Really?!"

"Why yes, lets go to the garage and check it out." James' father guided guided to the garage, which had a car and some pieces of a bicycle.

The little boy gasped, he ran towards the pieces and examined it. "Is this a bike?" James turned around at his father to him nod in response.

"But I don't know how to ride a bike." James stated quietly he looked down and started fidget with his hands.

"You will, with the proper training." James turned at his father as he realized what he meant.

The boy turned back the bike again and marveled at the thought of his dad teaching how to ride a bike, but there was also something in James' mind that he wanted to ask.

"Do you think that maybe… we can build it together too." James didn't get a response however, as he turned around and saw that his father was nowhere to be seen.

He searched all over the house but Jim couldn't find him, ran to his mother's room and woke her up out of fear. Barbara told Jim to stay in his room until she said so, he waited while sitting in bed for about an hour until he heard his mother crying in the living room. As James walked towards his mom, he feared that she found his father somewhere lying in the ground, sleeping and not waking up; but James saw piece of paper on the ground in front of Barbara. As James pick it up and read what was on, he realised that what happened was worse than he imagined.

His father had left them; his dad had left him right when he gave his birthday present, he had left him on one of the most important time to James; for the rest of the day James went back to his room and stayed there. James felt like he wanted to cry, he knew he had to cry; but he just couldn't. James felt emotionally detached with his feelings, his father ripped out a piece of him, and it was his innocence. As James blankly stared at the floor he made he made a promise to himself and to his mom; that he would never forgive his father for what he did and would forget about him.

And that's what he did, for ten years James no longer celebrated his birthday; and James decided to change his name to Jim, he left his birthday present in garage still in pieces, Jim decided to buy his own bike and learned how to ride by himself. He now stood by his mother side more than ever to remind her that she didn't need his father, they were fine on their own. But when he turned fithteen, Jim became the trollhunter; although Jim gained a new family and realized that he was finally free from Gummar's rein, Jim had loss so many things, Draal, Vendel, trollmarket, and humanity. With all that has happened, Jim managed to completely forget about his father, since now he had Arrgh, Blinky and Strickler to a father figure to him. After Gummar and Morgana defeat, Jim Lake Jr. was finally at ease.

In Hogwarts, the headmaster, Albus Dumbledore, was writing letter invitations for his students for this year. Dumbledore sighed calmly as he enjoyed the peace and quiet filling the room; he started to hear footsteps coming towards his direction and stopped writing. Professor McGonagall came in his office, speed walking with a nervous expression on her face.

"Professor McGonagall, is there anything you want to inform me?" Dumbledore asked as he started writing again.

"Yes, and this piece of information is something that is very important you hear." McGonagall stated as she walked closer to the headmaster; Dumbledore stop writing once again and looked back at teacher.

McGonagall gave heavy sigh. "It has come to our attention that Sirius Black has a son that lives in the U.S."

The headmaster's eyes slightly widen. "Are you sure?"

"Yes, we are; though Sirius has not him in over twelve years." The teacher said as she walked around the office. "Is he a muggle?" Dumbledore asked.

"It is unknown unfortunately, but that does not negate the fact that he could be in danger from you know who." McGonagall explained.

"Do you know where the boy is?"

"People have been saying that they've seen the boy recently in New Jersey."

"I'll ask someone to travel to the U.S. and go fetch the boy, we don't know how long it will take for this news to spread." Dumbledore worried that if Sirius did have a son, then he would in as much danger as Harry was currently in.

"And the boy's name? The headmaster asked before returning to the letters.

"His name is James Lake Jr."