The Gates of Time were located in a timeless dimension, shrouded in mist and in mystery. In this place, chronos meant nothing – kairos ruled here, and thus only an immortal being could survive for any length of time. Thus had the daughter of Chronos been selected to guard the Gate and to prevent the passage of any and all interlopers. She had existed for countless ages here and seen the rise and fall of many kingdoms, one of which had given her the ability to transform into Sailor Pluto, should she ever need to leave her domain.
Like all such empires, that one had fallen, but she retained the power, using it a thousand years later in order to aid the reincarnated warriors of that era to protect the planet called Earth. It was, perhaps, the help she leant to the Japanese-born girls that brought her to the attention of the wizards; she didn't particularly care to find out.
She was, however, amused that these mortals who called themselves the Senior Council had the audacity to direct themselves to her realm and attempt to relieve her of her duty. It had been intimidation and threats all 'round, until the tall Gatekeeper had stepped in and convinced the wizards that the best course of action would be to leave her in position. Three of them in particular had not been happy, though she had noticed that the one who would have been her replacement had looked rather relieved.
This, of course, had absolutely nothing to do with the visit she had paid the child two nights previously, graphically describing the absolute boredom and loneliness that came with the position of Guardian of Time.
And so did the wizards quit her domain, leaving her once more to herself. The speech she hadn't given her intended stand-in had been painfully truthful, and she always felt her solitude more keenly after visitations. Time went by – or in the case of the Guardian, around – and she was given permission to leave her station temporarily in order to assist the Sailor Senshi against the Death Busters.
The time she spent in Japan was far too short for her taste, and she found herself being forced to use her forbidden attack so that Sailor Uranus and Sailor Neptune could try to stop the onset of the Outsider known as Master Pharaoh 90. As punishment for breaking her father's Law and stopping time, she felt herself being transported to the Outside, her very mind ripped to shreds –
Her body gently cradled in the arms of the Gatekeeper as he pulled her to safety within her own realm.
From that time on, he would visit the Guardian, always seeming to know when she was at her loneliest. It was, perhaps, inevitable that these two enigmatic persons found themselves drawn to each other first as friends, and then as lovers. Theirs was a relationship built on silence and mutual aid, a simple love with little in the way of drama or tragedy, just as the two of them preferred.