"I hope Dad's proud… he's always looking out for me, helping me fix whatever situation is causing a problem. I feel his presence sometimes, and it's so strong that I know it's him… so I can't let him down now… I have to look after our family for his sake."
—Upsilon the Mink
Upsilon the Mink
First appearance Gem High
Appearances Gem High, Gem High: Year Two, Gem High: Summer Vacation, Tesla Boom, Camp Doubtfire
Biographical Overview
Name Arkanov Underwood the Mink (always goes by Upsilon)
Nicknames Uppy, Upsy, Upsy Daisy, "The Shadow Master" (by himself), Lose-ah (by Kestrel)
Age 20 years
Birthday November 15
Birthplace Merriway, Havendisch
Physical description
Species Mink, specifically a European mink
Gender Male
Height 4'1" (124.36 cm)
Weight 102 lb. (46.27 kg)
Fur/feather/scale colour Muted purple/blue
Eye colour Silver (originally bright red)
Attire Dark red pinstripe dress shirt, deep mauve vest, black boots, gray gloves
Alignment and character traits
Alignment Lawful good (formerly neutral evil)
Favourite food Cinnamon buns or cinnamon coffee cake
Likes Creating ice sculptures, staying in his home, playing with his shadow powers, hand sanitizer
Dislikes Too much social interaction (mostly towards strangers), extremely humid weather, germs
Relatives Valdus the Mink (father, deceased), Irmia the Mink (mother), Kestrel the Pika (adoptive sister), Seismo the Laemink (half-brother)
Friends Sigma the American Mink, Kestrel the Pika, Wizard Digby, Hyacinth the Steppe Polecat, Lunea the Black-backed Jackal
Neutral Alice the Fox, Irmia the Mink
Rivals Tesla the Hedgehog
Enemies The Infactuates, Dawn the Kuikon, Nightside the Malevolent Shade (from an alternate universe)
Skills and powers Shadow manipulation, can call upon Shades (his helpers made from shadows), swordsmanship, possession of others by shadows

Upsilon the Mink is a 20-year-old mink and is one of the friends of Sigma the Mink. Possessing the ability to manipulate and control shadows, Upsilon can bend them to create a shadow sword, which he uses primarily in his job as a knight of the castle of Gaiagon. He is voiced by good buddy Thesupernintendokid.

Upsilon is a fan character belonging to SigmaAlphaThree.


Concept and Creation

While currently being a fan character in the Sonic the Hedgehog franchise, Upsilon the Mink's original concept was that of being a human with the same name, in a universe not even related to the Sonic fanon, called Hyperion. This story was the same places where the name for Sigma originated. However, the idea was soon scrapped, and the first design of Upsilon as a purple mink was created. More tweaks to his design and backstory are expected to be made.


To Be Redone Soon


Upsilon is generally a quiet individual. His lonely upbringing molded him into the secluded person he currently is, although he doesn't mind being by himself; in some cases, he actually prefers being alone. He's more of an observer compared to others, and for this, he notices small details normal people would miss. Lately, he's been introduced to more and more people, so he's growing a bit more sociable, although it is a slow growth.

Even though he doesn't say much when in larger groups of people he doesn't know too well, he is more talkative around people he is close with (for example, Sigma). When he is around friends and family, Upsilon has a lot more to say, and much to his surprise, he can be rather savvy with his words. However, he rarely shows off his charismatic side to anyone, even with his friends.

Powers and Abilities

Shadow Powers and other Abilities

Upsilon's power to control shadows, or shadow-bending, originates from his mother's side of the family. His shadow-bending skills serve for a variety of purposes; they can be used for attacks (for example, the Shadow Overtake) as well as to disguise himself (for example, the Shadow Generate). In addition, Upsilon primarily uses a shadow sword in battle, which is very sharp and as such, it is able to easily slice through many solid and seemingly unbreakable objects.

Upsilon is also good with hand-to-hand combat and has great agility skills. While lacking in lower-body strength, his upper-half is abnormally strong, allowing him to perform great swings with his sword and punches at various enemies.

List of Abilities

  • Shadow Overtake: A move that causes a dark black mass to surround an enemy and cover them in a shroud of darkness, thus choking them. This can also be done by sending a stream of shadows directly into a person's airways, not necessarily by covering an enemy in darkness.
  • Shadow Switch: He can actually turn into a shadow cast upon a wall.
  • Shadow object creation: With his powers, Upsilon is able to make a wide variety of weapons and other non-weaponry objects that are made from shadow essence; a primary example of this is his shadow sword (seen above), and he is able to make a shadow shield as well, if necessary.
  • Shadow riding: If necessary, Upsilon can summon a wave of shadows to form underneath his feet, move them forward and, and he can ride on them. This is mainly used as a means of fast transportation for emergencies, or for going long distances.
  • Shade creation: Along with Kestrel's witch powers, Upsilon can create a small helper made from a shadow exterior and a magic core, made from an Animation spell, which brings the unliving shadowy husks to life.
  • Swordsmanship: Upsilon was trained a bit to hold a broadsword as a kid by his father, and after his father's death he continued to practice this skill until he became rather knowledgeable in the art. He is very capable with his shadow sword (among other sword-like weapons he can create with shadows).
  • Heightened senses at night: Due to his shadow manipulation abilities being much more powerful in the dark, Upsilon's senses, agility, speed, vigilance, and capability of controlling his powers are far stronger in the night compared to the day.
  • Upper body strength: His constant training with swords and melee weapons has caused Upsilon to possess a pretty large amount of strength in his arms, which enables him to carry out forceful downwards swings on his attackers with his sword.


Basic Stats (1 is weak, 10 is very strong. Total can't be greater than 40.)

Agility BPStarBPStarBPStarBPStarBPStar 5
Speed BPStarBPStarBPStar 3
Strength BPStarBPStarBPStarBPStarBPStarBPStar 6
Defence BPStarBPStarBPStar 3
Evasiveness BPStarBPStarBPStarBPStar 4
Dexterity BPStarBPStarBPStarBPStarBPStar 5
Intelligence BPStarBPStarBPStarBPStarBPStarBPStarBPStarBPStar 8
Skill BPStarBPStarBPStarBPStarBPStarBPStar 6
Total BPStarBPStarBPStarBPStarBPStarBPStarBPStarBPStarBPStarBPStar 40


Since light and shadow cancel each other out, Upsilon is greatly weakened by the use of light against his shadow powers. However, this weakness can only occur when a light is directly used on him while his powers are activated, not necessarily when he's out in the open and not fighting.  He also has extreme weakness in his upper body after his powers have been used for an extended time. At that point, he resorts to hard kicks to take out his enemies.

His powers also need to be "recharged", or he needs a resting period right after intense, energy-draining battles. This, added with his upper-body weakness after battles, allows him to be an open target for remaining enemies.


Irmia the Mink "..."

Kestrel the Pika

"My annoying little twat of a sister. But I love her dearly."

Sigma the American Mink

"A good friend of mine."

Wizard Digby

"Eh... in small doses, he is fine, I suppose."

Seismo the Laemink

"In even smaller doses, he is just barely tolerable."

Ryder the Mink

Upsilon and Ryder met in Gem High, and they became close friends afterward. Ryder usually hangs with Upsilon and the rest of the minks. Upsilon and Ryder are pretty close when it comes to similarities as well.

Tesla Hunt the Hedgehog

Tesla and Upsilon had a tight rivalry since the beginning of Gem High. They both despise each other.

In Tesla Boom, there was a brief period where they worked together.



  • Upsilon's cuffs on his jackets have faded shreds floating in mid-air. This is easily done by his shadow manipulation powers (although at first, they were in his design just for a cool effect).
  • Upsilon has a British accent and never uses contractions in his speech.
  • He has a talent for making ice sculptures. Upsilon is very secretive about his hobby, however, and has only shared information about it with only a couple of people and he keeps all his sculptures in the freezer underneath his house.
  • If he was a human, he'd be 6'4" (193.04 cm) and 206 lb. (93.44 kg).
  • He loves tea. Not bubble tea, mind you – real tea. Sometimes he puts milk in it, though.
  • He prefers if he's called Arkanov (ar-can-awv), but the name Upsilon has kind of stuck.
  • He does sometimes wear pants, but he prefers the shirt-no pants look rather than the other way around.
  • He has felony charges against him in his home country, Havendisch.