They first met at Heliopolis, when Mwu requested permission to board the Archangel. They were comrades, and their conversations were based on business of commands and replies. Because Murrue became the captain rather unexpectedly, she had to trust in his plans and experience. She relied heavily on him for the first leg of their journey and listened to his advice.

When the Archangel landed in the desert, Mwu came to her office to discuss their gameplan, but also to check to see if she was alright. Even though they were still formal around each other, they do show concern for one another, and perhaps even flirt a bit. When the battle starts, again, she turns to him for advice, and he assures her, while being playful.

As their journey continued, they became more comfortable around each other. When they were in Orb, he took her side against Natarle. He tried to cheer her up, and she teased him in return. They've become friends at this point, as she relaxed as soon as Natarle left, even though Mwu was still there. She saw him more as a friend than a commander.

Murrue may have come to care for him more than a friend as she begged him not to leave after the battle outside Orb. Unfortunately, after landing in Alaska, Mwu was given the notice to be transferred to California. She didn't want him to leave, as she saw him off with tears in her eyes. He didn't want to leave either, because he went against his orders and went back to the Archangel.

After getting out of Alaska and finding their way to Orb, their relationship turned more intimate. When Murrue asked him why he came back at JOSH-A, he answered with a kiss.

When Mwu came back from Colony Mendel, he confided in Murrue about his father and Rau's words. He felt responsible and angry for the incident, and she was there to comfort him.

Before the final battle, Murrue went to the hanger to see him off. She looked worried, so he assured her that he would be right back, with victory in his hand. However, the Dominion prevented him from doing so, as he took the blow meant for the Archangel, protecting her life with his.

Despite Mwu being a flirt sometimes, he really cares for her, because he admires her strength and compassion. Because of his lonely childhood, and growing up in the military, Murrue's compassion and warmth really touched him. She taught him to trust and love. And he loved her enough to die for her.

Murrue can be hard on herself sometimes, and she needs Mwu there to help her relax and laugh a little. She can always depend on him to be there to offer an assuring word (or a slap on the back), and just be there for her.

Their relationship grew and developed gradually. They were comrades, then friends, before lovers. Their relationship is based on trust, admiration, and companionship. They believed in each other's abilities, and can always depend on each other for support.