Mikado Ryōko

Ryoko Mikado is the school doctor at Sainan High. She also helps out other extraterrestrials on Earth in various manners, usually those dealing with medical care, though she does offer students like Rito and his friends a variety of her own concoctions and some help concerning matters from space.

Appearance
Mikado has green eyes and brownish red hair, she also has pointy elf-like ears that she hides underneath her hair to blend in with other humans. Mikado often wears a lab coat, a pink top (that slightly shows the top of her breasts) that's held together by a belt on her waist and a black skirt. She has a slender and mature body that quite a few girls in the series envy her for. Her three sizes are B95-W58-H91. When she is not wearing clothes, her underwear mostly consists of lacy lingerie ranging from black to very dark blue and purple.

Personality
Mikado is kind to others, especially her students, including Rito and his friends, and would get mad at anyone who would hurt them (Chapter 79).

She also shows that she is comfortable enough to converse with Rito in a serious and mature manner (yet still obviously caring since she was thinking of giving him advice even when nobody asked her to do so, albeit she never came up with anything in the end), as seen when she approaches him one on one inside his room to say that she likes the planet Earth and that Rito must do what he can to save it while enclosing his hand on both of hers seemingly comfortable in telling him her serious feelings and thoughts about the matter (episode 25).

It is also notable that she doesn't react shyly nor angrily when he was obviously having a perverted imagination during the middle of the conversation, a trait of Rito that characters such as Saruyama notice whenever he's embarrassed or thinking of something ecchi, merely ignoring it even with his face visibly steaming red. Ryoko also has no problem with Rito seeing her almost naked with her clothes being melted by the king of Deviluke's plant traps or during their trip to the hot springs (where they shared a hot spring bath face to face with the inclusion of Saruyama).

Mikado is also optimistic and playful and is often amused by innocent perverted mishaps, especially around Rito. She enjoys teasing Rito's shyness around women, does not mind Celine or Rito molesting her by accident, and also appears to enjoy the sexual pleasure.

History
Formerly an operative for a shadowy, black market extraterrestrial organization named Solgam bent on overthrowing Emperor Gid, she fled from her superiors to Earth in hopes of hiding her identity. She now works as a doctor at Sainan High and runs her own clinic at her home where people and aliens go to for medical help, the latter group in secret.

Mikado has met Yami prior to start of the series, with Yami coming to her for treatment, shortly after her first Darkness Tranformation, full of injuries but with no memory of how she got them.

Powers and abilities
Though she has no unique special abilities, Mikado is a highly skilled doctor for both humans and many different species of aliens and an expert on a number of extraterrestrial matters. Although, in the anime, she is quite good at using her medical skills in combat, shown when she restrained Pikari using nothing but a roll of gauze. She is very knowledgeable about herbs and medicines, and she may use them for varying purposes and sometimes even a little mischief.

She also has knowledge and access to various equipment of alien technological origin, including a regeneration tank much like the one used in Yami's creation and childhood, which she used to treat Yami's overuse of her powers. It is both her vast medical knowledge and her access to highly-advanced alien technology that enables her to achieve scientific feats that are currently well beyond Earth's capabilities: She was able to construct an artificial human body for the ghost Oshizu to use as her own physical body like a living girl.

Trivia

 * Due to her pointy ears, Mikado has an elf-like appearance. She is not actually an elf, as elves are typically portrayed in fiction as being shorter than her established height of 171 cm, or 5'7".
 * While the field of her doctorate is unknown despite medicine being her implied profession, the fact that Mikado was able to construct a physical body for Oshizu's ghost to inhabit suggests she has a secondary grasp of bioengineering. It is unknown how intimately she has this knowledge; her use of a regeneration tank for treating Yami would imply a cursory grasp at worst and a tenuous one at best. Furthermore, it was never shown how she made Oshizu's body, so the ultimate extent of her bioengineering knowledge is unknown.