Invading of the Strongest demons ever

In the vast area of land on Earth, There were demons gradually invading everywhere. Demons were gradually taking over the world at that time. An Immortal demon king named "Zurich" ruled the demons he was clearly strong and powerful. There were some parts of the world the demons haven't yet reached. Somewhere in the uninvaded places was a young boy named "Son Bakhita". He was the youngest one in the Bakhita family. His ancestors and his entire family were all demon slayers.The demons were defeated many million years ago by the help of his ancestors who sacrificed themselves for the world. And were known as heros. Although it has been a long time since demons were defeated, their family have been training for unexpected situations like this . When they heard of the demons invading the world panicked and no one could stop the demons except the "Bakhita family" although there were other families who were talented in cultivation and strength, they couldn't stop the demons because of their crazy regeneration abilities . Bakhita was only 7 yrs and the weakest in the family. So when the demons almost reached their town, The Bakhita Family hid their youngest son on a tree in the forest. He was there with his nanny while his family fought the demons. After about a month the nanny told him to wait while she will go and check the battle if it has ended. Bakhita waited for another month but she never returned so he began wandering around in the forest. Two weeks later after walking he arrived at a village. "Sir please where am I" Bakhita asked a man there. Who replied that he was in Kumwa. He asked if the war has ended and that had the demons had been defeated but the man sighed and said "although the demons have decreased in number due to the sacrifices of the Bakhita family, they haven't yet been defeated and will come again fully prepared next time ". He was heart broken to know that all his family perished. He cried his eyes out while saying that if he were stronger his family wouldn't have died. Meanwhile he is been looked for by his people in his village. They stopped looking for him after a while . He left the Kumwa village and went back into the forest dejected. On his way back he heard that a demon slayers sect has been opened recently and is looking for young children and youth to train them. He was clearly surprised and happy. He started making his way there and asked the people there for directions. When he reached there he was surprised to see soo many people there. And before you will be allowed to join we will weigh you to see your weight and those who were skinny were sacked and since he hasn't eaten proper food for days, he was sure that he wouldn't qualify but he wanted to try his luck.