After 4 days, over 12 hours per day, I had killed more than 3,000 Seafury cyclops. Wiping the island, one at a time, time of day, Quag alive or dead... non of it mattered. Finally, I pulled Quag off the island and kited him over to the undead island, stopping in the water from time to time to make sure he caught up. Once on the beach of the undead island, I rooted and killed him. Went back to the cyclops island and killed those on the beach nearest the water, and closest to the druid ring. UNBIELIEVABLY. A tainted spawned. Killed it. As I was turning around to look behind me for the corrupted, which doesn't spawn on top of tainted corpse, I spotted the corrupted walking to the beach real close to the druid ring. At the same time, I saw another tainted spawn not far to the west of the ring, back off the beach some.
Killed the first corrupted, ran over and killed the second tainted. Behold, a second corrupted spawned. Killed it and announced in general chat that the druid epic corrupt Cyclops part was rotting near the druid ring.
If the spawn of tainted seems broken, drag Quag to the undead island, root and kill him there. Go back to Seafury Cyclops island and try just the ones close to the water and druid ring. No need to wipe the whole island, or even all of those in eyesight. Place holder seems to be the one that spawns on the little spit of land sticking further out than the general beach. Again, the tiny peninsula closest to druid ring.