Iris.EXE

Iris.EXE is a NetNavi and the younger sister of Colonel.EXE. She always traveled through the real world in a CopyBot. While she had a crush on Lan Hikari, and almost worked up the courage to tell him, she decided against it as it would never work out between them. She was deleted after fusing with Colonel.EXE in order to delete Falzar/Gregar once and for all.

Games
In the games, Colonel.EXE was made to be the perfect military NetNavi, and Iris.EXE was made when Wily extracted the part of Colonel's data that allowed him to control machines. While she led Lan throughout the course of the game towards his goals and provided him CopyBots whenever necessary.

She was later kidnapped by Mister Wily and used to control the Cybeasts Falzar and Gregar, but in a turn of events she remerged with Colonel.EXE and used their combined strength to beat one of the Cybeasts while MegaMan.EXE defeated the other. Unfortunately, Mister Wily had programmed Colonel and Iris to be deleted when they remerged, and the result was just that.

Anime
In the anime Rockman.EXE Beast she is the younger sister of the Beyondard Colonel.EXE, and first comes to earth to locate the Synchronizer: Trill.EXE. She is Colonel's emotion data given form, and at the end of the anime partly merges with him, enough to return Colonel's emotions data but still remain as a net-navi. She always loved her older brother and was sad when Colonel was gone. She also has a Netnavi, but it is just an extension of her that allows her to operate in both worlds with ease. She is seen by Trill as an older sister, being refered to as onee-chan.

Trivia

 * As mentioned above there was only one instance of a navi falling in love with a human. This was revealed right before Iris merged with Colonel in the game, as she said, "Lan Hikari... I..." As Colonel replied,  "What is it you want to say?" as she replied, "Nevermind... I'm just a net-navi after all."
 * There was an event in game that was a tribute to megaman x4 in Battle network 6 where Colonel EXE. was about to attack Lan but Iris EXE. stepped in the way to defend him.-- Megaman Patch