Koropokkuru are a race of small people in Ainu folklore. The name is traditionally analyzed as a tripartite compound of kor or koro ("butterbur plant"), pok ("under, below"), and kur or kuru ("person") and interpreted to mean "people below the leaves of the butterbur plant" in the Ainu language.
The Ainu believe that the Koropokkuru were the people who lived in the Ainu's land before the Ainu themselves lived there. They were short of stature, agile and skilled at fishing. They lived in pits with roofs made from butterbur leaves.
Long ago, the Koropokkuru were on good terms with the Ainu, and would send them deer, fish and other game and exchange goods with them. The little people hated to be seen, however, so they would stealthily make their deliveries under cover of night.
One day, a young Ainu man decided he wanted to see a Koropokkuru for himself, so he waited in ambush by the window where their gifts were usually left. When a Koropokkuru came to place something there, the young man grabbed it by the hand and dragged it inside. It turned out to be a beautiful Koropokkuru woman, who was so enraged at the young man's rudeness that her people have not been seen since. Their pits, pottery and stone implements, the Ainu believe, still remain scattered about the landscape.
"Small human-like creatures that have kind, calm personalities. Once coexisting with the Ainu people of Japan, there was a fallig out at some point, and they disappeared."
A Koropokkur can be found in West Shinbashi discussing treasures. The Koropokkur will display pride in his leaf, finding it to be durable and practical. He finds it to be the best treasure out there, although he specifies that Shabby Building Material can outshine it. If the protagonist has the relic in his inventory, he'll show it to him without giving it away, convincing the Koropokkur to reward him with an Ice Gem. The exchange can only occur once.
If the protagonist tries to speak to Koropokkur while interrupting ally Cironnup's turn, the Cironnup will instead successfully begin a special conversation with the Koropokkur.
Conversation
[Cironnup stepped forward and began talking to a demon!]
Cironnup:
Hey! It's Koropokkur!
Koropokkur:
Oh? And who are you? Can't say I've seen you before...
Cironnup:
Oh, right... I guess you wouldn't remember me... Say, did you used to live in Hokkaido?
Koropokkur:
Hmm... Yes, I suppose I did.
Cironnup:
I knew it! I used to live in Hokkaido too! I used to see you all the time under the butterburs.
Koropokkur:
Hmm... You know, that does remind me... I did often see a little fox there...
Cironnup:
Yeah, I think that was me! Probably!
Koropokkur:
Well! What a pleasant surprise to run into an old neighbor here. Ahh, those were lovely days... I must say though... This country has changed a lot since then...
Cironnup:
Those days in Hokkaido were so peaceful... I wonder if we'll ever get to go back?
Koropokkur:
Who can say...? It all depends on what ultimately happens to this world. All we can do in the meantime is stay strong...
Cironnup:
Yeah, you're right. I gotta be strong!
Koropokkur:
Mmm. That's the spirit, lad. Ah, well... You can have this. Hope this helps.
"Small human-formed demons from Ainu legend. Called "One that lives under Fuki", they are considered to have a kind, calm personality. Once coexisting with the Ainu people, there was a falling out at some point and it is said they simply disappeared. They were believed to have inhabited Hokkaido even before the Ainu."
—Devil Summoner: Soul Hackers compendium
Devil Summoner 2: Raidou Kuzunoha vs. King Abaddon[]
"A small, human-shaped demon of Ainu legend, it is believed to have a calm, kind disposition. Though they once coexisted with the Ainu, at some point there was a scism and they simply disappeared."
—Devil Summoner: Raidou Kuzunoha vs. King Abaddon details
"Small humanlike demons from Ainu legend. With a name meaning "one who lives uner Fuki," they are considered to possess a kind and calm personality. They were believed to have once coexisted with the Ainu people, but, after a fallin-out of sorts, they simply disappeared. Some even claim that the Koropokkur inhabited Hokkaido long before the Ainu."
—Soul Hackers 2 demon info
Koropokkur can be found in the Central Line as a common enemy, as well as Saizo's Soul Matrix 1F. He can give Ringo the Glass Shitoki accessory as a level up gift after he has learned all of his skills, which increases the wearer's Defense by 17 and increases their AGI and LUK stat by 3.
Persona 5[]
"Small human-like creatures, that have kind, calm personalities. Once coexisting with the Ainu people of Japan, there was a falling out at some point, and they disappeared."
Koropokguru in Royal loses his resistance to Gun damage. In addition to this, he can no longer learn Rakunda via level up, with the skill being replaced with Sukunda instead, and he is now the first Persona to learn Climate Decorum. When itemized during a fusion alarm, he instead yields a Mabufu Skill Card.
The Shadow of Heiji Ono will take the form of Koropokguru when confronted in Mementos during the "An Elderly's Meaning of Life" request. While he is normally only weak to Fire skills, if he is fought when the Weather is Rainy, he will also be weak to Electricity and Nuclear skills. After being defeated, he will drop the Nuisance Beltaccessory, which gives the wearer the skill Ambient Aid.
Persona 5 Tactica[]
"Small human-like creatures, that have kind, calm personalities. Once coexisting with the Ainu people of Japan, there was a falling out at some point, and they disappeared."
—Persona 5 Tactica background
DemiKids Light & Dark[]
"A gentle demon that loves the simple things in life and prefers to stay out of sight."