Looking for a recent manga about a boy who wants to join a knights order.
He starts out weak but quickly gains power.
He lives with his mother alone.
His training master later reveals he is his father.
He joins an academy as a defensive knight, but also trains as an agressive knight.

Shen Yin Wang Zuo?
Started out from a novel if you want to check it out.
Shen Yin Wang Zuo (Novel)

Thank you, that was what I was looking for.