MTL - Chapter One of the Night - Chapter 86 pretty good

Maid, older sister, younger sister, and even mother, all of them.

A novel adaptation of K, focused on the history of the blue clan and the events which led to Munakata Reisi’s appointment as the current blue king.

Anyone who could construct a stable Spell Model could become a Wizard — that was the Wizards’ ultimate secret! Having been given a new life as the son of an aristocrat and armed with a super quantum computer from his past life, Spell Models came as easily as breathing to Merlin. With this overwhelmingly huge advantage, would Merlin become the greatest Grand Wizard of all time?

- Description from Novelupdates