Even though I played Grim Dawn for maybe 2k+ hours, I only ever fought Ravager once, years ago with my Retal Warlord back when it was insanely overpowered when Oathkeeper released.
Since then, I go hostile with Barrowholm, 99% of the time. So finally decided to give give it another whirl with my vitality Ritualist on Elite.
Mostly unoptimized hodgepodge of vaguely vitality relevant gear. Don’t even have all the skill points from the campaign gathered yet.
Expected to get bitch-slapped nearly instantly due to my atrociously low DA and armor, even though I do have a 210 OA debuff on Siphon Souls. But turns out that with good piloting and kiting around the altar, the fight is actually somewhat manageable. What made it doable was the MVP of the fight - Ill Omen. Keeping the debuff on the Ravager the entire fight made his damage actually almost manageable. I have Will of Rattosh bound to Ill Omen and the Life Leech resistance reduction actually made it possible to leech off of him enough to somewhat sustain through the fight. The first half that is…
The first 50% of his healthbar was actually pretty easy, the other half really tested my piloting skills and mastery of the skill rotation to constantly keep him debuffed and leeching off of him just enough while he was slowly being chipped down by the DoTs + totems. He moves so fast it was occasionally actually kind of difficult to hit him with the small 2m AoE of Ill Omen 
If Ill Omen dropped for more than a second or even worse, Will of Rattosh, Mark of Torment and Health Potion was the last failsafe before death. Several close calls but managed to stabilize in time. Circling the altar or something during the fight was very important, because it allowed me to get in occasional healing ticks from Wendigo Totem, which was a ton of additional sustain with my huge HP pool.
Took 2 tries overall. Died at first when he was at around 25% health due to me not having perfected the needed skill rotation. Checking Grim Tools, the difference between Ultimate and Elite is not that large. His OA/DA are mostly the same and he just has 10% more Vitality resist and 10 million HP. So the fight would just take longer. The real problem at the moment is actually his damage. It goes up about 17% between Elite and Ultimate. I still did get hit often enough, even during the kiting which would most likely make it just enough for me to not live through it. But with some more finely tuned gear, it should be somewhat doable in Ultimate too. Overcapping Ill Omen for this fight is also probably a good idea. Could have had 2% extra damage reduction on him, which is pretty significant.
Just wanted to share the mess of an incomplete build that I managed to kill the Ravager with 
Now I can consistently run him on Elite. Time to stock up on those Dreadgazes.
EDIT:
Just got a nicely rolled one on my 3rd kill. A worthy prize and most likely the final upgrade for my helmet slot:
