The 10th Class Lout of the Knight Family is a Manga/Manhwa/Manhua in (English/Raw) language, Action series, english chapters have been translated and you can read them here.
The Summary is
The human world is on the verge of destruction after the attack of the Demon King, ‘Erodin’.
After the fight against the Demon King, the Gold Dragon ‘Exigar’ is reincarnated as a human ‘Kain Logdel’, who is a lout that knows nothing about magic.
While trying to escape from his sword-crazed family’s duties to stay at the training camp by hiding his sword skills, Kain is on the verge of being exiled because of the unexpected message from his Family Head…
Amidst all of this, the Demon King, with her new appearance, is also looking forward to reuniting with him?!