I'm on my way to the imp badge, beat the twisted experiment.
Get adrenaline and reform and invest points into vitality, then you will eventually beat him. You just have to stay alive untill his withdrawal is used.
lol HenryFleming gregor is easy..:
1) Toxicant form: +40% dmg
2) Shadow Blend: 400% speed
3) Agile exposure: +100% dmg
4) Withdrawal: Att for 260% of speed, strength and instinct
= 11000 dmg
This works against everything..