To my knowledge, Werewoods pure faction has yet to be done at 500 without potions. The Idle One had a strategy for 200, and completed 300 with the same team. (Post directly after the one underneath), and describes his logic in greater detail in post 1429. (I’ve noticed there is a difference in the Post numbers in the website bar, and those on the side bar, perhaps due to post deletions, or something. It’s off by 18, depending on how far up the posts are.)
I will look through for any additional more information and strategies, but for point of reference/comparison, I did just today complete it at 300 with no troops with medals, Hoard at 133, and Urskaya at 15. No faction pet bonus, which would change if I make it to 500, and I’ll edit tomorrow when I can check my other pets.
Edit: I found my pets are both 29 away from becoming Mythic. Plus a bunch of food. Here are my stats for them:
I also had Guild Bonus of +4 Life and +4 Armor. Someday we’ll finish all basic tasks again.
I went topside because Legendary room was Dark Cabal, and Sacrificial Priest, and he did sacrifice Dokkalfar for me. I did lose a troop in the second room a month ago at Horde 100, and it took me this long to save the gold to get Horde to 133 (+18 Magic).
The final battle I entered with the Bird, the Bear and a Torbern. Strategy kind of goes out the window when the troops change form several times per battle, but whatever. I got lucky that the enemy never shape shifted, and then with the last troop ready to cast, I set up the board so his cast would give me a four match.
Cedric Medal and two Yasmines, because those are the only ones I have. 
I should’ve taken a screenshot so I could remember what the other 2 rooms were. My Bird killed the Bear with a Torbern cast, and wounded the enemy Bird, but then died the next turn. The Bear killed the next two, and it’s explosion set up a favorable outcome for me.
In Conclusion: It will be some time before I am ready to tackle this delve with a Faction team at 500. By then, perhaps my two pets will be Mythic, the Hoard will be 300 plus, and I will have a favorable path to navigate.
If the top path has Tangled Path, that is an obvious avoid. But if it has Sacrificial Priest in the Epic Room and one of the Ultra Rare (Corrupted Altar), that would be lucky indeed. If the Bottom Path has Dark King’s Hoard, it might be worth doing. 10% Deathmark could work out about as well as anything. Although surviving that room with 4 troops is not guaranteed. Probably best avoid that. But I’ll avoid rooms that have 50% skull reduction as well, such as Bulette Lair.
Upon further reflection, maybe I’ll just avoid the whole endeavor. Good luck to those who try.