Real Man - Chapter 566:

After 2000 years has passed, the ruthless demon lord has just been reincarnated! But his aptitude at an academy for nurturing candidates for demon lords is, “Inept”!?

Having the capability to destroy humans, elementals, and gods, after a long period of countless wars and strife, Arnos the demon lord became sick and tired of all that and longed for a peaceful world, so he decided to reincarnate to the future.

However, what awaited him after his reincarnation is a world too used to peace that his descendants became too weak due to a huge weakening in magical powers.

Arnos enrolled in the Maou Academy established to find any students that might be the demon lord’s reincarnation, but his powers are too extraordinary that those in the academy couldn’t properly judge his powers, so he’s regarded as an “Inept student”. Being underestimated and avoided by most people there, he recruited a girl friendly to him, Misha, as his subordinate and comrade, and strives to climb to the top of the demon race hierarchy to one day reclaim his former title and status.

After breaking up with his girlfriend, he accidentally acquired a genius system and rose from there against the heavens, becoming invincible..

- Description from Novelupdates

This is a world where a king is the most powerful.

Four years ago, Kazuma Kannagi was defeated by his cousin Ayano Kannagi for the right to be the successor of Enraiha, a sword passed down in the Kannagi family. His defeat, along with his lack of talent for En-Jutsu, the fire arts, the Kannagi’s specialty, resulted in his banishment from the family. Now, Kazuma returns as Kazuma Yagami, a skilled master of Fū-Jutsu, the wind arts. At the same time, a number of murders at the Kannagi residence perpetrated by a powerful Fū-Jutsushi cast suspicion on him.

Volume 1-6 makes up the main story. Volume 7-12 are various short stories, also known Kaze no Stigma Ignition.

Note: Only v4 epilogue remains untranslated for the main story.