User blog comment:B214/Volume 21 info & spoilers/@comment-93.105.246.116-20160606130720/@comment-93.105.246.116-20160606143115

Well yes I know all that but by that logic he would be creating those sacred gears while on the battlefield.

Also he would not be fighting durring the time of Christ as he was his earthly manifestation. As the True Longinus was described as "the spear which pierced the flesh of god".

Which means he must have taken breaks from the battlefield and had time to regain his strength.