My tried and tested Koshchey & Azar method:1. Find Campfire2. Make sure you are in nighttime, but not too far - by now you should have nighttime talents which will give you an edge3. Full Moon, Maribor Forest, Wolf, Wolverine, Willow (definately), Kiss, Petri's Philter, Golden Oriole (unsure if effective on Koshchey's venom), Shrike (not nec.), Tawny Owl. Drink these and rest as necessary. You should leave the fireplace without any toxicity.4. Have a Blizzard, plus Swallow and White Raffard potions handy.5. Perun rune stone both your silver sword and steel one.6. Go to entrance to Koshchey encounter and drink a swallow. Save.7. When encounter occurs, immediately drink Blizzard. Use Strong Style with Silver and kick it's butt.8. Continue through and wipe out Azar while still under the effects of your potions (you won't need Blizzard with Azar).Do note at after fighting the Koschey, you will constantly loose life if it has had a good go at you. But with a decent skill level and your full moon potion, it shouldn't kill you.I can never tell what does this- it is like Bleeding, but without the icon warning.