That Inferior Knight, Lv. 999 is a Manga/Manhwa/Manhua in english language, Adventure series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

Due to misunderstandings of the boy, he makes both enemies and allies angry!?

From 「Manga UP!」 (Square Enix), he may be strong, but can’t be ignored!!

The supposedly weakest boy who mastered martial arts and magic, the world shakes his misunderstanding!?

“Hmm…I have no talent.”… is what Yuan grew up in the mountains thinking. He’s a normal kind-hearted boy, but of the unusual things about him, is that his parents are a sage and a master martial artist. In other words, the world’s strongest. Since Yuan was told he was the weakest, he leaves home to make his dreams come true.

“Eh!? Is it really possible to be defeated with a mere finger-flick by an 8-year-old kid?”

“You heard the hero was the weakest member? You’d have to be out of your mind to fight that!”

“Armies of Angels? You mean the harmful birds? I’ll just remove them altogether!”