Now I know Seigebreaker is not the hardest boss in the game, however people like to kill him with 5 stacks of NV and possibly use MF gear.
I found a bug, that I have been meaning to record and share with you guys, that makes this boss a walk in the park.
A few things I need to explain first,
-The exploit only works with a pillar being alive and well, if it gets broken, your glitch is also broken.
-Seigebreaker does 2 small jumps to signal a charge then a gurgle before charging.
-A charge or any attack will break the pillar.
-If you are far enough away from Seigebreaker when he wants to charge, he just wont.
-Any disabling effects can and probably will cause the charge to happen instantly, so beware when taking companions (blind/charm).
Ok so basically if you want to see the video, I've made one http://www.twitch.tv/actionpigeon/b/320719900
You have to position the boss here below this pillar:
You stay at this location until the boss does his 2 jumps to signal a charge then, and quick as you can, move roughly to the spot shown here:
The boss will not follow, even though pathing should allow him to figure out that you're far away from him and also the quickest route is clockwise around the pillar.
Hope this helps someone, please feel free to ask questions if there are any.