Neoui Aiga Aniya

Callia Taxicate was a mere commoner until she saved the life of Simon Tereloane, the son of a duke. In return, the duke helps make her commander of the emperor's knights and she becomes a war hero. Though she only sees Simon as a friend, the two unexpectedly spend the night together and she ends up pregnant! Terrified that he and his noble family won't accept a child out of wedlock, Callia runs away to raise the baby on her own. But how long can she hide this secret, especially from the father?!

(Source: Tapas)