Soldier of Time

Haruka & Michiru's relationship with Setsuna.

As Sailor Pluto, the guardian of the time gates, Setsuna shares the heavy burden of being a solitary guardian. Like Neptune and Uranus, Pluto's mission is to guard the solar system from outside invaders. This means she was forced to spend her time utterly alone, with only the light of the Silver Millenium to guide her. She's also the carrier of the third talisman, the Garnet Orb.

Haruka and Michiru are first reacquainted with Setsuna when she awakens as Sailor Pluto; their planetary symbols glow on their foreheads and they are transported to Setsuna's location. Together, they defeat a daimon attacking the inner soldiers and explain why they are so distant and what their mission is. The three of them share an immediate bond as they are once again reunited. Once their mission is complete and the Death Busters are destroyed, Setsuna, Haruka and Michiru decide to raise the newly reborn infant Hotaru together, becoming a family.

Haruka and Michiru both care deeply about Setsuna; the three are inseparable when they become reunited. Haruka and Michiru fully understand what it's like to be utterly alone for an untold amount of time and therefore understand and sympathise with Setsuna more than any other soldier could. They generally agree with each other and they share the same attitude regarding their mission and how to accomplish it, even if it means upsetting the other people they care about.

Setsuna also cares deeply for Haruka and Michiru. As they become a family, Setsuna finds herself no longer alone in the world.

Soldier of Silence

Haruka & Michiru's relationship with Hotaru.

Hotaru is the soldier of death and rebirth, Sailor Saturn. When she first appears, she is sickly and her body is mostly composed of cybernetic implants to keep her alive, as she suffered as a victim of a serious fire that killed her mother when she was younger. Hotaru's broken body eventually becomes a vessel for the evil Mistress 9, but her desire to protect those important to her is so strong that she is able to awaken as Sailor Saturn.

Haruka and Michiru's initial mission is to stop Sailor Saturn from waking. In their past lives, they witnessed Saturn's ability to bring ruin to the world around her and in order to stop that from happening again, they will do anything even if it means murdering an innocent child. This puts them at odds with the younger soldiers, who have grown attached to Hotaru and feel that they have no right to decide the outcome of her life. Neither woman is without pity, however; they take no joy in the idea of having to end Hotaru's life, and feel sorry for how she's been forced to live until that point. Eventually, Saturn awakens anyway but everything works out; Hotaru is reborn as an infant and Haruka, Michiru and Setsuna decide to care for her themselves.

After settling in together, Haruka becomes Hotaru's "papa." She's on diaper duty and is responsible for Hotaru's play time. They seem to spend time playing a game where they simulate the growth of the solar system so it would seem Haruka plays a part in Hotaru's education as well. Haruka seems to dote on Hotaru quite a bit, at one point worrying about picking up diaper supplies for her even though she'd outgrown them.

Michiru and Setsuna share the role of Hotaru's "mama" and Michiru is in charge of cooking and watching after Hotaru's health. She also spends time teaching Hotaru and other children how to play the violin. At one point, Hotaru breaks some of Michiru's expensive collectible plates. Michiru is annoyed at first but doesn't seem to mind; she's more concerned about Hotaru. Michiru also seems to be genuinely concerned over Hotaru's occasional change in personality from a happy and energetic child, to a cold echo of Saturn.

Both Haruka and Michiru are incredibly happy when they're spending their days taking care of Hotaru. I think raising Hotaru gives them a chance to experience of having a child together, something that they would never have had the opportunity of pursuing because of their duties as soldiers. They both believe it to be a dream come true and enjoy it to its fullest as they know it will not last forever.