An army consisting only of one man: Ven.

Going by the nickname "rhobiusvoid", Ven is a highly dangerous man, that seemingly has his right arm replaced with that of Alastor's right arm, giving Ven the powers of lightning. It is unknown as to why this is, but one can only image what kind of horrid events can spark from one such as him.

Especially given the shocking power he can provide with such a limb.
Don't actually take any of this seriously. I'm just some guy with an imagination that runs wild.