Gate Keepers 21(2002)

Gate Keepers 21

32 years have passed since the initial defeat of the Invaders. A.E.G.I.S is all but dismantled now and has become an underground organiziation consisting of only a few Gate Keepers left to save humanity. One of the members, Ayane Isuzu, is sick of society as a whole, though she continues to defeat the Invaders out of spite for her father. Suddenly, she learns of the revival of Machine General (Kikai Shogun) and Devil Count (Akuma Hakushaku), but a mysterious ghost girl now accompanies them. It is up to Ayane and the remnants of A.E.G.I.S to stop them and save humanity once again.

(Source: Anime News Network)