I've played against quite a few of those beasts and killed them. in the arena yesterday I fought a guy that had one and I killed his whole team but the wlovenfiend and all five of my heroes could kill him for over 2 minutes. how is that it was only lvl 135. What talents and weapon is good for the beast
Level 25 active is huge, even from 21 to 25 is an insane defensive boost. His recovery works pre-mitigation if I remember correctly, so without -hp recovery debuffs on him it's pointless to even try and kill him.
From my personal experience, -80% hp recovery is barely not enough from my Toxic Shaman. But after I upgraded TS' active to 25 to get -85% hp recovery I haven't met a Wolvenfiend I cannot beat.
Really tanky Wolvenfiends will reach ~80% dodge unbuffed with a high level Dragon Heart. On top of that he'll reduce all damage by 80%. On top of that he'll heal 60% of the (pre-dmg reduction) dmg he receives. And on top of that he reduces skill dmg by another 80%.
You need to counter at least 1 of those 4 things. Since you cannot remove his DMG red, other than Ironclad's active, you'll need to unload your hp recovery abilities on him and/or dramatically reduce his dodge. Dodge is fairly easy to counter, but cannot be fully countered as you really don't want hit rate talents so you'll have to do it with your own weapon and enchants.
Edit: To clarify his pre-mitigation heals a bit further:
Let's say your Abyss Demon hits Wolvenfiend for 100k with each hit (taking an easy example). Wolvenfiend then immediately rolls for his 75% chance to recover 80% of dmg taken. If it succeeds, he heals back 80k. BUT meanwhile his dmg reduction chews off 80k of your 100k AD's hit, meaning you only deal 20k dmg per hit, but he's healing 80k back if he procs his heal. In other words: for every 20k dmg you deal to him, on average he'll heal back 60k of it. Hence the 80% hp recovery not really cutting it yet, not reliably anyway.
With -80% hp recovery, for every 20k (after dmg red.) dmg you deal to him, he'll heal back 12k, which isn't so bad. But because of his Dragon Heart he'll have a chance to restore ~12% health when he dodges. It's fairly easy to reach 500k health on Wolvenfiend, so that means he'll heal for 60k, which is reduced to 12k by your -80% hp recovery debuff. 12k might not seem like much, but you're only dealing 20k dmg per hit, and you'd need an insane AD for it to reach that.
Edit2: This is all from my experience though, it's rough to find proper information about him but Wolvenfiend's heals actually healing pre-mitigation dmg is the only explanation he's able to survive for that long even with 5 decent heroes on him.
I could of course be wrong, feel free to point out flaws.
There is one more thing you're missing. I really didn't want to share but oh well. If you use Ambrosia as an aid instead of healing for 80k he heals for 112k. That also applies to the dragon heart heal and healing skills applied to him. That makes him almost invincible.
I've faced him in arena where he changed into a wolf, I brought him down to 0, he changed back into a human and in seconds he was at full health again.
To counter him not only do you need hp recovery debuffs, you also need insanely high equipment power. You do up to 50 percent more dmg if your equipment power. At that point you just out muscle him, but good luck beating him if he has a golden dragon heart. If his equipment power is higher than yours then he takes even less damage. There's even more secrets to making him stronger. I've met one that I'm sure has solo'd his way to deity using only Wolvenfiend.
He is very popular since he came out. Every base I attacked has wolf. He messed me up in arena, fod, few times since can't kill him. I am working my wolf up to see if using wolf to counter wolf will work.
He surely is a key player in hero coli, hero trial, arena, gc, guild boss, Def when my wolf is capricorn, lvl 170 with skill 15 along with ent sc bez aids!