Popular description
"Once every 100 years, a Water Fairy implants an egg into a person who then becomes the Guardian of Fairies. This time, the responsibility falls on Chagumu, the second prince of the New Yogo Kingdom.
Chagumu's life isn't easy. The king finds Chagumu an inconvenience and attempts to have him killed. As a result, the queen asks a female guard, Valsa, to protect Chagumu. In addition to this, beings from another world, known as Nayugu, constantly attack him in order to eat the egg carried in Chagumu's body."
The genres don't list schoolgirls anywhere though so it seems unlikely to be a priority for me
This 26 ep show is easy to find as a 1-26 torrent though, for anyone that really wants to watch it.