I was Reincarnated as the 7th Prince

A mage, lacking both talent and lineage, is burned to death by the magic he loves. He's reborn as Lloyd, seventh prince of the Saloum Kingdom, with his past memories intact. One day, in a forbidden library, he awakens a demon that wields ancient magic...

After making the Demon Grimoire his familiar, Lloyd sets out in pursuit of a dungeon with magically enchanted items and encounters Tao, a martial artist who uses Qi techniques. Lloyd assumes the alter ego of Robert and heads deep into a dungeon with her.

Deep within the dungeon lies a demonic lich that has laid many adventurers to rest. After forcing Robert to escape, Tao faces the threat alone, but is overwhelmed by the difference in power. However, just as the lich is about to finish her off...

With an interest in weapon enchantments and their effectiveness, Lloyd joins Albert and Sylpha on a monster hunt. After meeting Tao and reaching their destination the group encounters a pack of bearwolves, who regenerate unnaturally quickly.

Just when it seemed Sylpha was able to overpower the pack of bearwolves, the demon Pazuzu emits a miasma that has the knights collapsing to the ground. Once even Sylpha and Tao are rendered unable to retaliate, Lloyd finally makes his move.

With his new bearwolf, Shiro, in tow, Lloyd visits his sister, Alieze, in order to learn how to communicate with monsters. Afterward Lloyd is reunited with another brother, Dian, a blacksmith who is seeking to create the ultimate Spellbound Sword.

The kingdom has been infiltrated by a girl named Ren from the Assassin's Guild.. Upon learning of her special ability as the Poison Blighted, Lloyd tracks her back to her hideout, sneaks in, and is attacked by a group of assassins with unique abilities.

Having formed a connection with the Assassin's Guild members, Lloyd's curiosity is captured by the leader Jade's teleportation ability. Lloyd and the others head to Lordost Manor, where the guild is happy to be reunited with Jade, until...

Ren is confronted by the demon lord Guisarme, who has stolen Jade's body and teleportation power. Guisarme is intent on seizing the bodies of the Assassin's Guild as well, when Lloyd arrives in the neck of time to defend them.

As Lloyd and Guisarme engage in fierce combat, the members of the Assassin's Guild are cornered by a horde of demons. Using the control of their abilities given to them by Lloyd's spell, the Guild resists, but are gradually overwhelmed by their enemies.

Guisarme's teleportation-powered offensive barrage leaves Lloyd perplexed. Having come to a realization, he attempts a physical attack with a magic-absorbing sword named Spelltaker, aiming to decipher the nature of Jade's stolen power.

Guided by Jade's will, Lloyd deciphers the spell for teleportation. Pushed to the brink, Guisarme unleashes an attack powerful enough to reduce anything to oblivion, the Mortal Dark Sphere. At long last, this climactic magic battle comes to a conclusion.