SpoilerHe has a brief crush on the vanship captain Tatiana Wisla but soon forgets about it realizing the futility of it as he moves on to other things.
Around the end he leaves the Silvana to train again as a rifleman in a secret joint operation to take back the battleship's Claudia engines and free the world of the Guild.
At this time he meets Dunya Scheer from the Disith fleet, also involved in the operation. He and Dunya fall in love with each other, climaxing in Mullin asking Dunya to go on the same ship together. Dunya accepts his request, as the operation to take back the ship's Claudia unit begins. The operation ends with Mullin taking the unit back, but being gravely wounded in the process, believed dead. The epilogue shows that he survived to be with Dunya and live on a farm alongside Dunya's siblings. Many viewers mistakenly assumed the child shown to be Mullin's son. Additional materials state the child is Dunya's younger brother.