Prairie

Prairie (プレリー) is a character in the Mega Man ZX video game. She is the current leader of the Guardians, having the position since the original leader disappeared. The Guardians take in people on a voluntary basis to defend "Frontier" areas from Mavericks and discover what causes these outbreaks. They are considered an unofficial part of Slither Inc. and their headquarters is the giant airship known as "Guardian HQ".

History
Prairie took command of the Guardians after the original leader (who was revealed as Ciel) went missing after an investigation of an "Outlands" area involving the appearing Maverick attacks. At the start of Mega Man ZX, she hired the Giro Express to transport the Biometals "Model X" and "Model Z".

It is revealed in the game that Prairie is over 100 years old (yet she looks like she's only 14-16 years old), as she was present when she saw Ragnarok breaking apart in the atmosphere or when she sees Zero and Ciel going to fight a swarm of Mavericks, and later during the time of the Models' first discovery. It is also hinted that Prairie may be Alouette from the original Mega Man Zero games herself (her stuffed doll, which Alouette always carried, and her reference to the original leader as 'Sis', which Alouette always used for Ciel).

Mega Man ZX
In Aile's storyline, Prairie is hinted to have fallen in love with Girouette, being said that Giro reminded her of someone she knew before (an obvious reference to Zero), while in Vent's, it has been hinted that she starts to like Vent a bit also. Also, in Aile's storyline, you can see Ciel once you have finished eight missions.

Mega Man ZX Advent
In Advent, Vent/Aile bring the Guardian HQ in to invade Ouroburos, calling it their airship. It isn't explained what happened to Prairie, but Vent/Aile mentions losing a lot of friends fighting Model W, suggesting Prairie may have been killed, leaving Guardian HQ to them (but this is extremely hard to prove, as the two had been only saying it in general, not specifically).

Trivia

 * Her name means "meadow" in French.
 * Prairie's Japanese voice actor, Ryō Hirohashi, also voiced Alouette.
 * If Prairie is really Alouette, then she is the only surviving Mega Man Zero character to be left with an actual physical body (Zero and X are Biometals). This excludes Ciel, as she has disappeared. It would also mean that she is 200+, because the ZX series is set 200 years after the MMZ series.
 * In Prairie's room, there's Ciel's winter coat, pictures of Zero, Ciel and Alouette, and dolls of every Cyber-elf. Also, the video screen in her room depicts a scene from Mega Man Zero 2 when Zero and Ciel talk.
 * When a Pseudoroid is defeated with a level 4 victory, a doll of that Pseudoroid will appear hanging from the ceiling in Prairie's room.

After you Defeat Prometheous, on the Guardian HQ, He has a Conversation with you. He Makes a Statement to Prairie,"So your not from this time either". Which gives a little more suppourt to the theory that she is Alouette