Harpuia, Fafnir, Phantom, and Leviathan are four robots high within the Global Network hierarchy, just below the Council. Simply mentioning them to an enemy power is enough to make them reconsider their war plans; the Guardians, as they're known collectively, totaled an alien power by themselves.
Only they and the Council are aware that an integral part of their mission is to get Megaman killed.
This is my second attempt at Classicizing the Guardians, the first attempt being crap. All four are based on X, like in the Zero series; the GN thought X's was an efficient model, even if they hated his big brother.
Harpuia's horn-things are carried over from attempt #1, as are the gender issues. Megaman, his friends, and some peons lower on the GN totem pole know Harpuia as a woman, whilst her comrades and more important peons consider her a man. Harpuia doesn't care how s/he's referred to, nor does she care for her "secondary objective" (indirectly killing Mega so the GN can stop feeling inferior).
Fafnir's big guns became twin Busters, which he can only fire one at a time due to power issues. He enjoys battle to a perhaps unhealthy degree, but finds the GN itself boring and does whatever he can to avoid affairs that have nothing to do with fighting.
Phantom prefers getting his fights over with as soon as possible (he sniped a lot of said alien power's soldiers before the larger battle). He doesn't like conversing with his teammates or anyone else, frustrating the other three to no end. (Without the floaty visor-thing, his helmet would be a straight copy of X's.)
Leviathan is the only one who can fight underwater as well as on land (and who is definitely female). Like Fafnir, she loves battle, but knows when to listen to the GN because if not, there's a good chance they'll both be put under lockdown on the offense of being "too dangerous". Leviathan doesn't mind her questionable "secondary objective", as she sees Megaman as weak due to his pacifist nature.