These things are pretty rough. I've been playing through Pantheon, and after level three, I just can't die. At level 15, I can literally stand there and take all the hits from a bunch of Regulus, or even take all of Oak's whacks when in his 10-second-destroy-everything-before-he-dies mode.

Playing the Torch Bearer is fun, but after level 10 or so, with the right equips, he is literally -unstoppable-. Maybe downscoping some of the equipment would add a bit more challenge! His skills are well balanced with everyone elses, congrats on that. But when added with a few artifacts, Godly is the right term. (Too unbalanced maybe)

Also, we should add some different to the artifact abilities besides stunning, damage, etc. Such as, mass heal, where it heals all allies in an area, or some such. Add a "Use: heal target unit for X amount" with X cooldown. Maybe even add a minion-spawner, or the like. But with that one shield with 25% damage reduction, that's too powerful! Maybe make it physical percentage instead? Only?

Lastly, with a couple of balancing questions... When you kill a demigod, why so much gold? Kill like, 4 and you got yourself a nice powerful artifact.