Shigano Iori manga
Continuation of the prologue: Amanoiwato Hime. The Hinomoto Kingdom's Princess Guard - an elite squad that directly protects their royal princess. Kasuga Haru was newly appointed to this prestigious position and was next to the Kingdom's one and only princess. There's only one problem. Their "royal princess" is a hikikomori, a recluse who stuffs her room with video games and refuses to leave even a nanometer out of her room. Kasuga's special mission given by the Queen is to make Princess Terras into a proper human. Can Kasuga succeed in turning this otaku princess into a proper princess full of charm and beauty?
The time is probably the 21st Century. In the Hinomoto Kingdom where the king has the kingdom under control with somewhat of peace, 3 rookie military officers, Haru, Natsuki, and Touma, are assigned with a very special mission: To protect the King's daughter! The three rejoice at this unexpected mission that their lieutenant provided them with, and they quickly arrive at the princess' room but find out that the princess is different than what they had expected..... A princess guardian comedy now begins! The Story continues at NEET Princess Terrass