Otome

Otome are young girls who are trained to utilize nano technology and photon

About
Otome is the broadest sense operate as bodyguards, inforcers and servants to a specific master or country. Many countries value the military power that they provide and as Nao Yuuki points out the military strength of a country is often dependant on the number and quality of its Otomes. Rulers and high ranking officials of countries are often required to be granted Otome at young ages as Duke Nagi is merely a child and his country works diligently to make sure that he can obtain an Otome. When Nao Yuuki was nominated to become a Pillar the responsibility of becoming the Duke's Otome was shouldered onto Nina Wong.

Otome can clearly be classified as Super soldiers and their dispersal over a large period keeps a balance that masquerades as peace between countries while various bureaucratic struggles and issues arise by the continued use of this system. Regardless the ever-present need for Otomes stops countries from recklessly engaging each other for resources and keep a balance between all nations to prevent all out bloodshed and war.

However while this balance is often described as peace, the planet of Earl is in a state of a Cold War from all appearances: as various countries rattle to gain subtle advantages over others and various people in positions of powers utilize the powers that Otome provide in order to obtain a personal desire such as a higher station in life or more resources for themselves, the concept of peace slowly deteriorates and many notice the ever growing inevitability of a conflict.

Otome themselves are not looked upon as individuals with wills and feelings but instead as weapons and/or servants and their only true value is in their power. The educational process of the Otome re-inforces the belief that Otome are weapons of war, and many full fledged and student Otome seem to have an underdeveloped sense of self, likely stemming from the educational system prioritizing the Otome become an extension of their contractor. At least one Otome openly called hers to be her master and his wishes and orders absolute, and the very idea of an Otome abandoning her powers in favour of sexual feelings is looked down upon, and in some cases attempted at being policed.

However with the Otome's great power comes a price: should the Otome die than so will the person whom they made a contract with. Furthermore for an Otome to access her powers she requires the direct permission of her contractor in question whom than kisses the jewel to allow Otome to fight. The exceptions to this are the Five Pillars, five Otome who are contracted to the founder of the Otome system, and in a state where she is inable to grant this power. Instead the Five Pillars are capable of transforming at their discretion and their demise do not seem to affect Fumi in any noticeable way (possibly because of the amount of contracts she is bound to).

Relation to HiMEs
Whether or not the HiMEs that are mentioned in the second OVA and any sort of connection between Mai-Otome to Mai-HiME aside from the reused character designs are the subject of much debate. However at the very least the concept of the HiMEs as female warrior maidens who predate the Otome and who have some connection with their powers are canonized in 0.sifr.

Both Lena Sayers and her daughter Arika have demonstrated abilities as an Otome that defy the nature of all other Otome and leave many shocked as it. As both are implied to be a descendant of Alyssa Sears who was an artificial HiME the two could have some sort of genetic potential or latent lesser HiME powers as a result of their bloodline. However Lena herself seems to dwarf Arika whether by virtue of simply having a longer stint with her powers developing throughout multiple years at Garderobe (while Arika barely attended a year) or by being a bonified HiME herself as she has a mark in a place similar to Mai and Akira from Mai HiME. Lena's mentioning of this coming about as a result of time could imply that Arika also has the potential to develop HiME-esque powers as well, however some of this could also dwell in the uniqueness of the Blue Sky Sapphire which is able to maintain a Robe for Lena Sayers while other gems of great prestige and renown were not.