Guillain

Guillain (pronunciation: [ɡi'lɛ̃]) is an NPC in Dead Cells who provides the player with a Mutation between biomes — up to 3 total. 
After choosing mutations, the player can have Guillain reset them for 1,000 gold. A second reset costs 2000, a third 4000 and fourth 8000. 
Not much is known about Guillain. They sit happily next to the pile of corpses left by the Beheaded's previous attempts. Their proximity to the Collector suggests they know him or work with him.
Guillain resembles the merchants, the Blacksmith, and the Blacksmith’s Apprentice. These characters have a chameleon/goblinlike appearance, seemingly the same species. 
From the new heads in the "The End is Near" update, we're safe to assume Guillain is the name of the species, but is possibly also the name of all Guillains.
For good measure, here's a list of all Guillains as of the clean-cut update.
# The two Guillains that appear in passages
# The Blacksmith that runs the Legendary Forge
# Shopkeepers; the mimic will have shapechanged to resemble a Guillain but is not actually one of them
# The Guillain that replaces The Collector.(Only on 5BC)
# The one that appears in the Mimic Warning Lore Room, both inside and outside of the Bank
# The one in the Bank with the piggie bank, who appears to be fundraising for a party
# The one in the Library in the Bank
# The hairdresser, but not the hairdresser's daughter
# Various dead Guillians can be seen in the background of the Bank, as opposed to the more humanoid corpses in other biomes
Quotes:
* "I'm really happy I found this great stinking pile of corpses!"
* "You can't even imagine all the stuff you can find in here!"
* "By the way, it's an odd thing to say... But you... kind of look like these guys..."
* "Oh yeah, sorry about the smell..."
* "In any case, it beats selling a bunch of old ju... Stuff... Yeah, stuff."
* "Well, I'm going back to digging through the filth for some more goodies!"
* "I'll see you again, I guess..."
* "..."
* "Errrr..."
* "..."
* "cough"
* "..."
== Gallery ==
File:Pimp My Run Update Titlecard.jpg|Guillain chasing monsters with the Beheaded on the Pimp My Run update poster.