FINALLY! I did it! I beat schtupid Gao Ren!! Not only did I finish the quest but I *killed* him in one go! YESH!
I think my problem was that I went with everyone's suggestions to use a hammer against him and well, to be honest, I kinda suck at hammers.
So instead I rethunk my strategy completely. I pulled out all the stops and stocked up on large/bounce bombs, fitted my armor with bombardier jewels and switched back to my WoC: long sword, and proceeded to slice him to ribbons and bomb his ass. Not only was I more accurate, but I took much less damage because I was more fleet on my feet. I also found out from watching Nico Nico Douga that you can trigger the dragon skewer spike wall thing more than once-- You can do it once per 10 minutes. I wish someone had told me that earlier!
Man I feel so relieved now that he's out of the way. He was definitely a wall for me and I think he kinda traumatized me for a while. But now I can finally move on to the upper ranked elders. Yay! Go me! I'm unstoppable now!

Hurray!
TwiGGy11:49 PM CST