My Territory Changes Every Day, So I Turned Myself Into a Witch

[Gender Swap] [Light Yuri] [Gradual Transformation] [Lord] [Farming] [Fantasy] [Not Your Typical Power Fantasy] [Slow Burn] [Longevity] [Loli] After transmigrating to a fantasy world, Rey is reborn as the son of a frontier lord, the illegitimate child of the lord and a maid. So Rey has already resigned himself to living off his family and lying flat for the rest of his life. As long as he is useless, his brothers won't see him as a threat. But one day, his family suddenly prepares to leave him behind, leaving him alone to guard their territory as acting Lord. Rey is dumbfounded. Before he can ask what's going on, his father has already fled with his brothers. Only afterward does he learn that the demons of the frozen wastes are preparing to invade the continent. The border fortress where he lives has already been abandoned by the kingdom. His father left him there to die simply to earn the family a good reputation. Just as Rey is falling into despair, a Mutation System quietly appears. Its function is simple. Every day, a special mutation occurs somewhere in his territory. These mutations can be good or bad, and are completely random. But Rey never expected that... His very first mutation would grant him a Witch's Origin, giving him magical affinity on par with a witch. Even if he just lies still, his magic keeps growing on its own. What's more, Rey discovers that his daily Mutation System is changing his body in every way. From halting his growth and giving him fair skin and long hair, to changing his organs, altering his meridians, and enhancing his looks, among other things. To Rey's amazement, every part of him is gradually changing to become more like a witch!