welcome to the Wuxia type writing, this is just the manga, try reading the novel, lol...hey but it is worth the read even if you have less hair by the end of it
Actually , BTTH is much more worth reading than the other side stories.. Xiao Yan's quest to become stronger are much more detailed than the others including the fighting scenes.
And him being as an overpowering MC has quite reasonable.
1. He is indeed a reincarnated person with memories of his past life, though he doesn't mention what kind of life he has back then, but he was able to differentiate between the two worlds,
2. He has rare talent with limitless potential according to the fortune telling, that what was said in the chapter when he was to obtain the "shattering liger's roar" in the academy.
3. He is the successor of the Xiao Ancient Clan. A Direct descendant of his ancestor who is so powerful enough to be acquainted with the God Tuo She and trusted by him. Plus I think, Xiao Yan's mother's genes has some contribution also. His mother is quite mysterious.
4. He has a very powerful and talented Master who help him to nourished his rare talent.
5. According to his Master, his rare talent with limitless potential, his intelligence and being quick witted plus having his extreme extraordinary good luck made it possible to achieve what he has achieved so far. It is as if enough to call him "The God's favored Child".
Appreciating this circumstances made it all makes sense.
I used to like this manhwa. but the storylines keep on repeating the same pattern. the mc is too op and no one can beat him. then, he is being reckless and just show off his strength. i'm starting to lose interest already