Hardy (ハーディ Hādi) is the goddess of the underworld and ruler of hell. Her apostle is Giselle and her shrine is Belnago Shrine.
Hardy is first brought up when Rory shows fear of riding the Tokyo subway during her first visit to Earth, when she reveals that Hardy has asked for her hand in marriage. Hardy is the one who opened the gate in Japan. Her primary reason for opening the Gate can be summed up as "Because she wants something new in her world that will likely get her interest piqued". Another reason is to destroy the old system of the Empire by making them facing enemy far more powerful than them indicating that she aware of the tremendous military power of JSDF over the Empire. She also doubts that Gisele can beat the JSDF showing that she takes the military power of the JSDF seriously unlike Zorzal and his pro-war supporters.
Despite being worshiped by most mortals in the Special Region, she is shown to be neglect and indifferent with their pledge and suffering since she cares mostly for her own interests. Furthermore, she also believes strongly in the philosophy in natural selection in which she decided to look the others way when the Flame Dragon massacred hundreds of people because she viewed it just a powerful tool for her to destroy the Gate to prevent calamity of space-time continuum as well as destroying the JSDF to maintain the balance of the underworld since the Flame Dragon is the only powerful thing in the Special Region that can give some troubles to the JSDF. To her, human sufferings and activities are just mere entertainment. As the result of her heartless and selfish approach to her subjects, Yao and the rest of the Dark Elves, formerly her ardent worshippers, have since disowned her.
She is shown to be surprise and amaze to see that a human like Itami can defeat the Flame Dragon. Furthermore, she is also interest in the world beyond the gate in which she finds an amusing fact that the Earth has multiple gods for different field like Music, Wisdom or War. However, much to her dismay, she realize that none of the underworld gods from beyond the gate are matched for her taste since most of them are male (Yama, Hades, Anubis) and she even calls one of them ugly, especially Anubis due to his dog-like appearance. However, she eventually falls in love with Aphrodite, Greek God of Love and Beauty, to the point that she makes Itami to promise her a trip to the world beyond the Gate; much to Itami's dismay since he not even sure these deities really exist or not and the knowledge of them only come from the book of Earth mythology owned by Lelei.