Not particularly much (e.g. I know I did spine after him, and I have like 550k health in my spine vid , which even before the 5.4 buff is really not very much). I don't remember exactly how much, but he's definitely easier than the bosses before and after him, so if you can get to him solo, he should be a pushover.On an aside, what sort of gear level would be required to solo him as a Guardian?