That Time I Reincarnated In Gunreim

Dying because of a fatal tsunami surfing accident, Louis reincarnates as a Human with a thinned Blue Oni bloodline, granting him a smooth blue horn above his forehead. Taking account of his surroundings, Louis listened to his father epically proclaim him the first son of House Willow Cap of the great Equine Empire.

Gauging his surroundings, Louis realised he had a mom with magnificently big tits, getting placed on her lap to realise she had an enormous bulge. Putting two and two together, Louis guessed she was a futa, soon looking at his older sister to determine her gender, realising she was just a woman with a small chest for her age.