Ashen was a 
Raid Boss Lv. 3000 (65,000 HP) from the 
Celebration Event, fought at the 
Grand Colosseum in alternation with 
Agony. Despite its Raid Boss status, it was one of the easiest enemies to defeat in the game.
How to get it
Event boss (no longer available): it appeared every 20 minutes at the Grand Colosseum during the Celebration Event, alternating with Agony, and despawned after 9 minutes. It arrived accompanied by a group of 
Lightning Bandits.
What it drops
Summer TokenHow to defeat it
Ashen used the 
Lightning fruit but, oddly, only cast Lightning Orb [Z], a low-damage projectile, spending the rest of the time dashing. Stay out of range of the orb and manage the Lightning Bandits accompanying it - its dashes are barely a nuisance, it's a Raid Boss much easier than average.
Our take
Easy event boss and now unavailable - Agony's quiet younger sibling, to rush without stress if an event brings it back.
Update history
Raid Boss : Ashen·Released : Update 27.5
Bosses
Ancient Beast
Ashen
Awakened Ice Admiral
Beautiful Pirate
Bobby
Cake Prince
Cake Queen
Captain Elephant
Chef
Chief Warden
Core
Cursed Captain
Cursed Skeleton Boss
Cyborg
Darkbeard
Diamond
Don Swan
Dough King
Fajita
Fishman Lord
Gas Knight
Gorilla God
Greybeard
Heaven's Guardian