A Voice in the Cosmos
Sir Matthias is a knight - he was happy with the lord he served and his fellows. But when a castle falls from the sky and a monster destroys his home, he does the only thing he can think of - lead the monster to the local Beast.
The Beast does take care of the monster - but also flees to the cosmos, taking Matthias with him. He reveals he is a price in exile, and the monster an assassin sent by his brother.
Seeing no other choice, Matthias swears fealty to Prince Gloraonas, forcing the alien man to take him along as he searches for a new place to live in peace.
A slow paced slice of life science fiction story about a medieval knight making a home in space.