|Manga Debut|| Chapter 157 Voice only
Chapter 165 Actual Appearance
|Anime Debut||Episode 36|
Mercury has a very detached personality that can sometimes be misunderstood as absolute indifference. Her personality is sometimes misunderstood because she tends to deal with the problems of others as if they are trivial things not worthy of her attention, even if said problems affect her as well. Mercury is not completely devoid of emotion, however, since she does worry about Ayumi whenever Ayumi feels troubled and even immediately apologizes if she faces admonishment, providing that she understands that she is initially at fault.
As if to complement her impartial habits, Mercury also displays herself as one that seems to be in a constant state of drowsiness. Already seen as someone who appears to require a myriad of sleep, rarely does she have her eyes fully open even when she is awake.
Like her sisters, Mercury's true appearance is not revealed. Also, similar to her sisters, Mercury appears as an altered version of her respective host, Ayumi. Her skin noticeably darkens, and in contrast to Ayumi's dark hair, Mercury's hair is a silver-white color. She also acquires long bangs which set aside to cover one of her fiery-red eyes, and under each of her eyes is a set of two horizontal lines. Most of the time, Mercury either has her eyes half open or completely closed, giving off a sleepy disposition.
As one of the Jupiter Sisters, Mercury also has a halo and a pair of wings.
Mercury has been referred to by her sisters as the specialist with regards to unfamiliar and bizarre spells. As such, Mercury's sisters turn to her whenever they are faced with a spell they aren't sure how to deal with, such as Apollo's hydration spell and the teleportation spell used to transport Keima and Elsie back to the past.
As one of the Jupiter Sisters, Mercury is one of the goddesses responsible for the sealing of Old Hell. However, their actions inevitably trapped them along with the spirits they meant to seal. After an indefinite amount of time, the goddesses are ultimately released along with the spirits when the seal inexplicably breaks. Mercury is separated from her sisters, and manages to acquire a host of her own — Ayumi — by cloaking her presence along with the runaway spirit that possesses Ayumi.
Hours after Ayumi's and Chihiro's visit to an indisposed Keima, Mercury is shown to be conversing with an unknown person and gets herself reprimanded for being so detached regarding human emotions. Mercury apologizes about her remark with a wry chuckle.
On the eve of the Mai-High Festival, it is revealed that Ayumi is Mercury's host when Mercury appears again, consoling a depressed Ayumi after Ayumi decides to surrender Keima to Chihiro.
Following the events of Keima's rejection of Chihiro and the subsequent physical punishment Keima receives from Ayumi, Mercury and Ayumi are seen conversing in private. As Mercury attempts to console her forlorn friend, she is confused as to why Ayumi followed them even though she chose to relinquish Keima to Chihiro, all while saying that Ayumi is being inefficient in doing so.
The next day, Mercury presents Ayumi with a monologue regarding human emotions. Ayumi tries to silence her, but Mercury continues, saying that it is possible that Keima may like Ayumi. Ayumi denies her claim, however, and says that Keima's sudden feelings for her cannot be true since he went on a date with Chihiro the day before. Mercury disregards Ayumi's thoughts on the matter, and according to her, humans are completely incomprehensible, so nothing they do can surprise her.
Afterwards, Chihiro appears, and talks to Ayumi about her rejection from Keima. Following their conversation, Ayumi realizes that she is the one who has changed since she did not feel like she was actually cheering for Chihiro. Ayumi then asks Mercury what she should do, and Mercury replies that the rest is up to her, before fading away. Ayumi tries to reach out to Mercury, but Mercury gives no response, and retires deep within Ayumi's consciousness.Days later, during Ayumi's and Keima's makeshift wedding, Mercury emerges after Ayumi kisses Keima. However, she emerges while in profound slumber, and is unable to repel the Vintage agents currently surrounding Keima and herself.
At that moment, Diana swoops down and grabs Mercury while thanking Keima. She frantically calls out to Mercury, and Mercury subsequently awakens. Surprisingly enough, Mercury immediately recognizes Diana. Diana then tells Mercury that there are some things they must accomplish, but Mercury complains, saying that she has just woken up.
With the arrival of a new day, Diana and Mercury succeed in rescuing their sisters, and with the combined powers of the goddesses (and some assistance from the Runaway Spirit Squad), the Vintage hideout and the members within are eliminated.
Heart of Jupiter ArcDays after the events concerning the destruction of the Vintage hideout, the usual sleeping Mercury is seen being led by her elder sister, Minerva. Vulcan, Minerva, Mars, and Mercury resolved to gather because the former three noticed a dark energy surrounding Maijima High. As they approach the source of the miasma, the goddesses encounter Elsie, who is tending to an incapacitated Keima.
The goddesses then witness that the miasma is leaking out of Keima's body. A moment later, Tenri appears, and explains the situation to everyone: Keima's sudden collapse is to prepare him for travelling back in time to Maijima ten years ago. The present goddesses then realize what Tenri is referring to and at Apollo's arrival, they prepare an intricate magic circle to accomplish spacetime travel.
As they reach the culmination of their spell, Mercury admits that even though the resulting magic is perfect, it is the first time she has attempted using a barrier to contain — and to an extent, complete — such a teleportation spell. Moments later, Haqua and Nora arrive with the key (orb) that will aid Keima in his journey. Nora hands Tenri the orb, and Tenri asks Elsie to accompany Keima. With everything set, the goddesses transport Keima and Elsie back in time.The goddess are later summoned by Diana for the purpose of having a sleepover. As Mercury sleeps, her sisters engage in a less-than-polite discussion regarding Keima's potential partner (among the hosts) while his consciousness is back in the past. In the middle of the argument, Mercury rouses, and promptly tells her sisters that it will be better to wait until Keima returns to discuss his future. Soon after, she disregards what she previously said and announces that Keima is Ayumi's husband, consequently reigniting the argument from before.
Mercury and the others later sense an incongruity within spacetime. Realizing that Keima has failed, the goddesses all reflect on the mission and wonder if altering the past will have any adverse effects on their current time. Vulcan testifies that it shouldn't, since the purpose of the key (orb) is to make sure it doesn't. Hoping for the best, Mercury and her sisters scrutinize Keima's unconscious body.
To make most of their situation (or perhaps merely to pass the time), Mars decides to hold a lottery with Keima's body as the prize. According to her, whoever wins the lottery will have custody of Keima's body while he is still on his mission. A few of the goddesses voice their displeasure (namely: Vulcan, Diana, and Minerva), but Mercury brushes them off saying that panicking is useless since they all have equal chances, while Mars proclaims that only the strong of will shall be victorious. It is later revealed that Apollo is the victor of the lottery, so Mercury and her other sisters will have to be patient until their turn arrives.
By the time Mercury is revealed, she is already on good terms with Ayumi. Presently, it is unknown what Ayumi's first reaction to Mercury was or if she is even aware that Mercury is a goddess. Nevertheless, Ayumi seems to be rather close with Mercury and has even gone so far as to nickname her "Mel".
Mercury, being the youngest, loves and respects her sisters in her own way, even if she does not show it often. True to her nature, however, she deals with her sisters similar to the way she deals with everything: lethargically.
- The name Mercury comes from the Roman god, Mercury .
- In Roman mythology, Mercury is the god of trade and commerce. Mercury talks about how she's been to many places (relating to the ideas of trade and commerce), which may allude to why her sisters say that she has extensive knowledge of exotic spells.
- In Roman mythology, Mercury is also the messenger of the gods. He is often recognized by his winged sandals (also known as talaria) that bestow flight and incredible speed upon their wearer. This maybe a reason why Mercury (female) resides within Ayumi — who has gained fame as "Mai-High's Human Missile" — the fastest runner at Maijima High School.
- Curiously enough, the first capture of the series is Ayumi and the last goddess to be found ended up residing within Ayumi.
- Mercury's appearance is similar to Ganguro fashion of Tokyo, given by her dark skin and light colored hair.
- (To Ayumi) "The human world is quite interesting ... Human hearts are far more complicated and amusing than I had imagined..." (Chapter 157, p.9)
- (To Ayumi) "...Ayumi ... Don't cry Ayumi..." (Chapter 165, p.18)
- (Monolouge) "My name is Mercury. Although I have gone on many journeys, this is the first time I have explored the maze of people's hearts." (Chapter 173, p.8)
- (To Ayumi) "Haven't you noticed yet Ayumi...? The answer has already been given..." (Chapter 173, p.10)
- (To her sisters) "Well, well, exalted sisters ... wouldn't it be better to discuss that after Katsuragi returns? Katsuragi just embarked on a journey. Besides, Katsuragi is Ayumi's husband you know?" (Chapter 190, p.7)
|The World God Only Knows|
|Main Characters||Keima Katsuragi • Elucia de Lute Ima • Haqua du Lot Herminium • Tenri Ayukawa|
|Jupiter Sisters||Diana • Apollo • Vulcan • Mars • Minerva • Mercury|
|Capture targets||Ayumi Takahara • Mio Aoyama • Kanon Nakagawa • Shiori Shiomiya • Kusunoki Kasuga • Chihiro Kosaka • Jun Nagase • Tsukiyo Kujyō • Minami Ikoma • Rieko Hinaga • Sumire Uemoto • Nanaka Haibara • Yui Goidō • Hinoki Kasuga • Dokuro (Human) • Urara Shiratori|
|Minor characters||Mari Katsuragi • Keiichi Katsuragi • Miyako Terada • Izumi Ishikiri • Fujiidera • Ichirō Kodama • Morita • Hiyori Sakurai • Sora Asuka • Airi • Mobuko • Yuu Hatori • Yotsuba Sugimoto • Mai-High Delinquents • Okada • Yui's mother • Hiroyuki Ishigami • Yanagi • Shoutaro Shiratori|
|Novel characters||Tooru Amami • Asami Yoshino • Ikumi Yoshino • Shino Akuragawa • Aoba Fuse|
|Magi Kanon characters||Kozue • Bell Mark Atsume|