Fader is a boss with 25,000 health.
It resists pierce; fire and spirit do nothing to it at all. Blunt and slash land at full damage, so that is what to bring.
Its hardest hit is bite at 210 pierce, out of 10 attacks.
Some of what it throws is elemental, so fire and spirit resistance is worth having.
You cannot block flamebreath, so give yourself room to dodge instead.
Of everything craftable, 
Lightning Strike, 
Frostfire Sledge and 
Thunderblood Sledge put the most damage through what it resists.
It always drops 
Fader Trophy and 
Kindled Ribs.
Fader's arena is a coliseum in the Ashlands. Vegvisirs sit in the central towers of Charred Fortresses. Collect nine 
Bell Fragments from those fortresses, forge them into three 
Bells, and hang the Bells at the coliseum to wake him.
Fader is the hardest fight in the game and he checks everything at once. Bites and claws land for around 200 pierce, the flamebreath leaves burning ground, and his fissure attack covers the arena in spike fields, each marked by small green flames a few seconds before it erupts. He is immune to fire and spirit and resists pierce, so the tools are frost, lightning, slash and blunt. Bring 
Fire Resistance Barley Wine and the best food you can cook, keep the arena floor in your peripheral vision, and treat every paw movement as information. Short, patient rounds win this. Greed dies in the fissures.
The current endgame power, earned from the current endgame fight.
He drops the Kindled Ribs and his trophy. The ribs are proof of the kill; the power is the prize.
With devcommands enabled, this spawns Fader in front of you. The third number is the level: 3 spawns a 2-star.
Creature ID: Fader · all console commands and IDs