Actually it's possible to kill the guy solo (since I don't play multi), since I farmed the guy for quite awhile but got bored of it due to not receiving the materials I need for awhile. If it's the download one, do what admiredfob does in youtube it should work pretty well if done correctly. If it's the round one I just GS charge him to death on the first round with full diablo z and that diablo gs (forgot it's name), should put him into armor mode about 20-24 mins into the fight if done properly. On the 2nd and 3rd round I just use Uca/Uka GL and shell the hell out of him, though I use the skill gunnery master and sharpenning skill inc, I was able to kill him in the 3rd round with this trick, oh and no bombs too.
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Don't bother just to be better than your contemporaries and your predecessors, try to be better than your yourself, for this thing we call 'failure', it is not the falling down, but it is the staying down, you only fail when you quit.