A genius who makes modern and future tech in the past

Our big brained protagonist

Our protagonist goes by the name of Fony (pronounced pho-nee) , Fony Snark (the joke is that he is a Chinese knockoff of Tony stark because I don't care about names). Anyways Fony Snark or just Fony looked exactly like Tony Stark (iron man) except was wearing medieval Europe clothing and also didn't have glasses. Fony from a young age, irradiated massive amounts of big brain energy so much so that by the age of ten he had access to all the technology that we have in the modern world. He kept it all to himself as unlike other people, he wasn't too strong and technology allowed him to catch up.

His first creation that he actually intended on using was a special sword that could break any sword as long as the sword was not magically indestructible due to a special part of the the blade that would pop out snapping other swords like twigs. This made him a popular person to hang around as his "unbreakable" iron katana could destroy any sword. He had indeed turned left onto downtown coolsville.

The next thing he invented was a special gauntlet that could fire a hidden crossbow bolt out of it when he pressed a button. He ended up making two of them and then added magnets into the hilt of the blade and the gauntlets allowing him to hold his sword for longer periods of time with less grip being used. He still needed a way to help support his ground when using his sword so he made an entire specialized suit of armor that could allow him to jump up incredibly high, be incredibly strong, fly for short periods of time and finally allowed him to take hits that he normally couldn't. He ended up looking like a child sized version of Tony Stark wearing samurai armour.
He officially had arrived at the middle of downtown coolsville and he was loving every moment.

Everyone was amazed with him and his incredible abilities allowing him to fight with people who had trained for decades while he was only a 10 year old. But then one day someone challenged him to a fight using each other's swords and armour. The swords were the same type and so was the armour. The difference was though that Fony who was actually weak immediately had his ass kicked and his secrets revealed ending up with him exiled in disgrace. He had officially exited downtown coolsville and had entered its neighbor uptown losertown.

Skip ahead a couple years and now Fony looked exactly like Tony Stark (without glasses) and had invented similar technology. He could now fly as long as he wanted, fire laser blasts out of various parts of his armour and could make various items be made in his hands due to a newly made device known as the Pixelator. The Pixelator basically turned something you made on a computer exist in the real world after being generated pixaly. This process could take time but if the product was simple it would take no time at all. Fony eventually became rich selling his mass produced materials (not food tho as pixallated food tastes horrible).

No one entirely forgot about what Fony had done in his childhood and now wanted it to make up for it by giving his opponent from all those years ago a set of the armour and a katana with the exact same abilities to the man allowing Fony's opponent from all those years to have a trophy and a neat set of armor that he could use if he needed help winning a battle. Soon after Fony received word that his opponent wanted a rematch, both wearing the exact same armour and using the same weapon that Fony had used in all his previous duels. Fony accepted and soon it was the day of the duel.