Powers
Green has an odd power, in that he can manifest small, featureless sphere-like objects, two inches in diameter. These spheres then enter orbit around a selected target no more than twice as high as Green, which can be himself or even individual body parts. The speed, angle, and diameter of the orbit that the spheres make can be chosen by him, but regardless of those factors the spheres will move to intercept any object that attempts to come within a foot of their orbital path, not counting the objects they are orbiting or any sufficiently large object, such as a wall or the floor.
The spheres have an odd quality to them, in that they are completely inviolable. They cannot be shattered, destroyed, punctured, or otherwise damaged, as they ignore any force applied to them. Anything that cannot be intercepted is simply displaced without resistance. To say that that this is unpleasant is an understatement.

While his skill has been steadily improving over the years, Green is currently limited to around forty spheres.

Weakness
Apart from the great degree of protection that his orbitals offer him and other people, any sufficiently overwhelming attack could go over his wall. Once that happens, he is simply another human being. A human being in advanced armor, yes, but still an ordinary human with a beating heart and a head full of brain. Anything fast enough, such as a laser going at the speed of light, also has a very good chance of bypassing his defenses altogether.
He is also rather unskilled in encounters with other superhumans, being used to 'regular' gunfights, encounters with infantry and, at worst, artillery.

Notes
His powers cannot be directly used for offense, as he cannot control the orbs directly aside from assigning them orbital paths. The orbs will not go further than blocking or pushing an object out of the way. If needed, several spheres will remove themselves from their path to block any particularly large object.