"You were the maiden I noticed, Lady Serenity, not your mother--even if you weren't the holder of the silver crystal, you had the purest heart."
The guardian of Earth's Dreams and the protector of Elysion, the Holy Land of Earth, Helios is used to a lonely and contemplative existence. Cut off from all human contact except his two maenad guardians for thousands of years, when Helios meets Lady Serenity in the 20th century, he falls in love with her pure heart and earnest kindness.
Though it was difficult for Helios to wait over a thousand years for the girl he had met as a young teen to be born and return after meeting him to 30th century, Helios' wait paid off, and he is reunited with his love just before she decides to attend Goban high school. Helios is happy to attend school alongside her under the psuedonym "Hiroshi", though his years of isolation mean he is more than a little socially awkward and shy. Still, he is eager to assist Usako in trying to befriend Seisui, and when King Endymion begins to have doubts about his decision to allow Usako to attend public school after the dangerous Moon Senshi surface, Helios is the first to stand up for her and her abilities as a senshi and a team leader.
But when it's discovered that Seisui is, in fact, Sailor Titan, Helios begins to have doubts about Usako's desire to hide her from her parents attempts to bring Seisui to justice. After all, despite Usako's claims that she can handle Sailor Titan and her repeated assassination attempts, Helios begins to see that the bloodthirsty senshi is too much for them to handle alone...