Origin

Kirby hails from a large family that seems to all be members of the Greco/Roman pantheon. It is unclear whether they are avatars, like himself, or whether they are the actual gods.  It would be unusual within the world of Mage for people to be avatars of gods: all the other avatars are reincarnations of human heroes or at the most half-human/half-gods like Kirby.
 

He explains that while at a party he struck his mother (Hera?) and as punishment, his father (Zeus?) assigned him twelve labors to complete, after which he would be forgiven. He is visited periodically by his sister Athena, whom he calls "Theenie," and who delivers a brief idea of what his next task is. All of the tasks that he actually names follow fairly closely to the twelve labors of Hercules' myth.  He also has a brother, Apollo.  Kirby meets Kevin Matchstick and Joe Phat as they are about to invade a nest of harpies. He later earns his father's ire for receiving help with this particular labor.
 

Creation

Kirby Hero was created by Matt Wagner for his series Mage: The Hero Defined. He is loosely based on Matt's friend and fellow artist Bernie Mireault. 

Character Description and History

Kirby doesn't really change during the course of the story. He's macho: rash, brash and boisterous. He is not very considerate of how is massive fights will affect bystanders.  He disappears for days at a time and is often reluctant to get too tied up in other hero's affairs.  As Kevin says, he drinks like a fish and chases tail like a puppy.  His favorite expression is "Super Cool!!"
 

Kirby first meets Kevin Matchstick and Joe Phat when they are about to attack a nest of harpies.  Kirby brashly comes up and says he take them out by himself, and attempts to do so, but Kevin insists on helping.  They beat the harpies and rescue their man-slave, who turns out to be Wally Ut, a half-crazed man who claims to be Kevin's second mage.  The heroes ignore him and drive off together, having quickly bonded. Kirby recognizes Kevin right away and they discuss past adventures.  For instance, Kirby once worked with the Presbyter, and says that he said that Kevin was difficult to get along with because he always wanted to be the leader.  This is a classic Kirby tactic: being very direct and honest, making it clear that he has no interest in letting Kevin be his boss, but also saying it in a way that pokes fun and defuses his point with humor. 
 
Kirby is about to leave on his own, to continue his labors, but then Wally Ut tells him that Theenie, his sister, isn't coming to meet him to give him the next one.  His father is mad that he didn't beat the harpies on his own.  Kirby doesn't know whether to believe Wally knows what he's talking about or not, but he decides to tag along with the other heroes.  They hang out in the wilderness talking and comparing powers.  Kirby says he's a basic tough guy: unable to be hurt, can't get tired, super strong.  He lifts the Edsel to show off, although he says it's not a great example, it's just the heaviest thing around.
 
Then they travel on to Isis' house.  Isis is a witch and they hope she can tell them why they've been noticing such an amassing of evil creatures lately.  The heroes all smoke a magic drug that gives them a vision of a giant creature on a mountain.  In Kirby's vision, it is a green titan on a mountain with a background of red: for Kirby, red is the color of good magic.  Kevin and Joe take this to mean that this creature is behind their recent troubles, but Kirby isn't at all convinced that the vision was anything but a hallucination.  Just then, the house is attacked by the Sprigginflints, and the heroes go out to fight.  Kirby steals two of the Sprigs' boards and tries to ride them, unsuccessfully, and then decides to just bash them with a pulled-up road sign instead.  The Sprigginflints get away, and Kevin and Kirby argue with each other about who is to blame.  Kevin is mad at Kirby for throwing his sign in an attempt to hit them--who knows where it landed.  They eventually get past their differences, and the group rides up to Montreal, where their vision led them.
 
After a bit of partying, Kirby leaves the group to find his next labor.  He is sent to clean out some stables.  After he does, he runs into Kevin and Joe again after they destroy some gargoyles.  They join up for some drinks, but begin arguing again about their long term goals.  Kirby is not a fan of Kevin's leadership and the idea of looking for whoever is behind the grouping of evil creatures.  He just wants to complete his labors.  There, they run into the Monkey King, another avatar, who brings them news that even more avatars are arriving in Montreal.  Then Kirby takes them to Mount Royal, atop which sits an enormous cross.  They all recognize it as the mountain from their dreams.
 

Later Kirby and Kevin break up a fight between their fellow avatars the Hornblower and the Sun Twins.  After the Hornblower is very deferential to Kevin, as the King, Kirby can't help but make fun.  Then they are attacked by some hell-hounds, and Kirby dispatches several of them.  Right after that, their fellow avatar Dragonslayer comes up and challenges Kevin to a duel.  Kevin refuses, but the Dragonslayer sucker-punches him, which brings Kirby to a rage and forces Kevin to agree.  Kevin barely wins.  They return to their apartment to find Isis; she says that Magda is coming soon.  It is said that Kevin is destined to fall in love with Magda, and Kirby and Joe take the opportunity to tease him about it.
 

Then they go to a meeting of the avatars, to see if they can come up with a strategy that they can all follow together.  Kirby doesn't speak up, but clearly his heart isn't in the struggle, it's in his labors.  Just then, Theenie shows up to give him his seventh labor: to kill a bull.  She emphasizes that this time, he's not allowed to let the others help.  Once again, he leaves the group.  However, after Joe and Kevin interrogate a Redcap and get more info on the Pale Incanter, the force behind the forces of darkness, they track him down to see if he'll help.  They find him in a trashed room.  His brother Apollo had come by to gloat and they got in a fight.  They sit down, and Kevin finally coaxes his motivation to complete his labors out of him: he got drunk at a party and hit his mother so hard she barely survived.  So the labors are a penance for his deed.  Kirby still refuses to join back up with Kevin, but unashamedly asks him for some money.  Kevin begrudgingly gives him some and leaves.
 
Later, Joe is seduced and mentally controlled by a Leanhaun Sidhe.  Wally Ut finds out and banishes her from the apartment, but he is still under her control, so Wally goes to get Kirby to come back and help rescue Joe.  Kevin, Kirby, and the Presbyter go up Mount Royal to the cross, where they believe the forces of darkness are hiding.  On the way, they fight some frost pixies, more hell-hounds, and a cyclops.  Kirby acquits himself well against them all, other than getting his shoes frozen by the pixies.  The Presbyter then helps them see through the illusion of the cross, and they descend down into the faerie realms.
 

They come upon Cerberus, guarding a midnight maze--a portal leading to absolute blackness.  Cerberus breathes fire on them, and Kirby takes the opportunity to hide behind the Presbyter's fireproof cloak.  It turns out that fire is his only weakness; he has had dreams of dying on fire.  They all end up getting knocked into the maze, and while Kirby and Kevin fall back out into the cavern, the Presbyter is lost inside.  Kirby wants to go back for him, but Kevin insists on continuing the search for Joe.  Kirby is angry--is Joe the only one worth saving?  Then the Sprigginflints drop a huge boulder on them.  Kevin knocks Kirby out of the way and and Kevin is trapped underneath.  Kirby is angry because the boulder wouldn't have hurt him as much, he 's tougher than Kevin.  He ends up lifting the boulder, with great effort, then tossing it away.
 
They finally find Joe in the Leanhaun SIdhe's lair, where he is stuck in her webs.  A small faerie they saved earlier gives them a clue: it says the Leanhaun Sidhes are compulsive about counting, and if they see a lot of small things, they have to stop and count them.  Showing some smarts, Kirby crushes a small rock into pebbles and throws them on the floor, disabling it temporarily.  Even then, it takes one of his best punches without going down, and Kevin has to destroy it with the bat.  This is the second time Kirby, normally brash, thinks tactically.  He also used an oil drum filled with pebbles to make noise to scare the harpies earlier.  They save Joe.  Joe fixes Kirby's glasses, which have been smashed in all the fighting.
 
They happen upon a large group of Redcaps and defeat them, saving their intended sacrifice, Wally.  The friction between Kevin and Kirby increases.  Kirby has been continually annoyed with Kevin's overly-brusque leadership, and also seems suspicious of Kevin's relationship with his new love, Magda.  Then, Wally starts showing signs of actually being the second mage after all, and while Kirby and Joe begin to accept that fact, Kevin won't.  They have a conversation about the color of magic.  Kevin believes it must be green, but Kirby insists it's red, signifiying its ferocious character.  Joe thinks it's blue and Wally says it's purple.  Kevin just gets angrier as they others disagree with his bedrock ideas.  Then Wally sees a water-wight, which he says is a sign of an upcoming death.
 

Finally they come into a huge arena, where the Man-Mountain of Dzoxk is waiting for them.  He is a giant golem with a helmet that resembles steer horns.  Kirby immediately believes this is the answer to his labor about the bull.  He insists on trying to defeat it by himself, but he doesn't realize that it is carrying a shield that contains an enormous amount of Kevin's magic, which Emil, the Pale Incanter, has siphoned off over time.  His attacks actually hurt Kirby.  Kevin joins the battle, which makes Kirby very angry.  Kevin is always insisting that they all follow his quest, but Kevin won't respect Kirby's quest, which must (according to Theenie) be accomplished alone.   Kevin knocks the Man-Mountain back on Kirby, squishing him underneath.  Kirby's glasses are broken once again, but he is unhurt.  He jumps on the Man-Mountain and rips off one of his horns.  Kevin blasts it with his Bat, but the golem absorbs the energy and becomes more powerful.  As Kirby once again remonstrates with Kevin to stay out of it, the Man-Mountain picks up its broken horn and stabs Kirby with it, mortally wounding him.  Kevin, enraged, destroys the golem.  Joe tries to help him, but Kirby's flesh is so tough, it resisted his attempts to mend him.  Kevin, in a fury, uses the Bat to resurrect Kirby, a process that destroys the Bat.
 
Wally Ut wakes Kirby up.  He finds that the Man-Mountain has been destroyed, and is infuriated.  Kirby decks Kevin, stating that it would have been better for Kevin to leave him to die than have him interfere with another one of his labors.  He has had it with Kevin's my-way-or-the-highway approach.  In the end, Kirby leaves Kevin for parts unknown, taking Joe Phat with him. 
 
Later, as Kevin talks with Mirth, he learns that not only is Kevin an avatar of King Arthur, but also of Gilgamesh, and that Kirby is not only an avatar of Hercules, but also of Gilgamesh's companion, Enkidu.

Powers and Abilities

Kirby has super strength and resilience.  He is easily able to lift several tons, though his upper limit is never discussed.  He was able to throw a 55-gallon steel drum high in the air with no effort, and throw a road sign so far they couldn't see where it landed.  He seems to be stronger and tougher than Kevin Matchstick, as demonstrated when he lifted a boulder that Kevin couldn't lift (although Kevin had no leverage).  Lifting the boulder took a lot of effort.  It must have weighed many tons, but nowhere near, say, 100 tons.
 
The boulder almost crushed Kevin, but Kirby said that while it would have hurt him, it wouldn't have hurt hum nearly as much.  He was able to jump off a high cliff into a river with no ill effects, and was sat upon by the Man-Mountain with no real injuries.  He was able to shrug off attacks by Redcaps and various monsters.  On the other hand, when he was hit by the Man-Mountain of Dzoxk using the power of Kevin's magic, it hurt him, and he was able to be mortally wounded by it, using a horn as a weapon.
 
His jacket, with it's lion symbol, was said to give him extra protection, although this was never really shown.
 
His weaknesses include fire and a need to wear glasses.