In the interests of moving the plot forward, here's the dope on the mage; he's protected by a multilayer of defenses; one is a shield against objects passing through that is grounded in the dirt over a ley-line, so the dirt itself can pass. He has a shield up against missiles, so an object passing through the first shield like a clod of dirt or an arrow, will fail.

Figure out a solution to that particular problem. ;) Hint: Longtok's arrow passed the first shield, but didn't penetrate the second. 

There are multiple solutions, but yeah, let's get that narrative going a bit. ;)