Sunkiller sanctum delve T11 Marksmanship hunter

This particular scenario, where the final boss is split up into 3 "Corrupted Umbraroots" is a particular pain. Each one has about half the normal amount of health of a regular boss, but their mechanics are TWICE as bad. They have a charge attack, it leaves a slime trail, and they also have a breath weapon that summons adds. WAAAY overtuned. And the adds he summons may look like they are dinky mobs that can be burned down quickly, they are NOT. After struggling with one of them I did a quick internet search, which is a long pause in the video I didn't bother editing out (c.f. channel title), I found that the solution is to switch Valeera to tank mode to fight them. After doing that the fights were much more manageable.