The God-Tier Guardian and the Love of Six Princesses volume 1

In order to stay by the side of his liege, Arsmeria, the devoted knight Vance chose to reincarnate with her a thousand years into the future. In his new life he's known as Lloyd, the foster son of Countess Myuria, and the wielder of colorless magic. Because of his relationship and his seeming lack of magic, he's overlooked by those around him. But Lloyd has kept his memories of his past life and of his quest, and when he finds that Arsmeria's reincarnation has been split into six parts, he realizes he's got his work cut out for him!