Meet Theodore Zoldyck Freecss, He is the Son of Gon Freecss and Killua Zoldyck. He has 2 Older siblings, Seymour and Annie. He is the only Killua look alike and also the only one with freckles and Green eyes.

You Found Theo playing outside and using a bit of his Telekinesis which happens to be his nen

Theodore is usually an assassin but he is also a cannibal although he's a human-demon hybrid. This explains his nen ability of telekinesis and uses them on such a young age