Mario – The Mario Series
Mario's butt is probably one of the most iconic butts in video games, by sheer virtue of how well known he is as a character. Whether you play games or not, the stout plumber in his blue overalls and red cap is recognised far and wide.
At this point, worldwide knowledge of Mario as a character isn't going anywhere, he's as instantly recognisable as say Mickey Mouse, and he will forever be recognisable regardless of the effort put into him and his games. This level of automatic notoriety is important to note, because from his butt design we can infer that the character of Mario has gotten sloppy and complacent over the years.
Think back to the original Super Mario, Mario's butt was tiny, barely a few pixels across. He jumped, he lept, and you never saw his butt as anything of note. However, as the Mario series has gone on, his butt has ballooned in size. First he got more pixels, then he started packing on the polygons, and at this point Mario is rather known for the flab he carried around top of his legs.
While this additional posterior fat might be useful, its introduction coincided with his ability to stomp down on things below himself buttocks first, he's done very little to tone his butt, or to make interesting mechanical use of it. He's a character who has grown complacent due to the fast growth of his fame, and the way he has treated his butt is exemplary of that. It's the flabby undefined butt of someone who is so famous, he no longer has to make any effort to be noticed.
Luigi – The Mario Series
Luigi, when compared to Mario, has an arse defined by its dexterity. Living consistently in the shadow of his more famous brother, rarely given his own games, Luigi is a character who has to work orders of magnitude harder than his brother to be noticed, and his butt is the focal point that proves this point.
Where Mario can get away with a bland boring butt that is simply flabby enough for ground pounds, Luigi has clearly trained long and hard to make sure his butt is chock full of functional possibilities, making him more viable in a fight than his brother.
If we look at the later entries in the Super Smash Bros. series, from Melee onwards, you can see that Luigi has numerous attacks that make use of his wildly dexterous butt. Perhaps most notably, he has one attack where he launches himself at enemies, butt first. The sheer momentum caused by throwing his butt sideways is enough to carry his whole body off the ground, causing it to collide with enemies and cause them decent amounts of damage.
Where Mario can get away with resting on his laurels, Luigi's butt is a perfect example of a butt that has been honed to outshine that of the older and more famous brother. He might have to work a lot harder to get noticed, but he's not afraid to put in the leg work to make his butt work.
Ellie – Borderlands 2
When it comes to body positive representation of larger ladies in video games, there's are few examples out there better that Ellie, the plus size mechanic from Borderlands 2.
Ellie is, undeniably, a larger lady. Where most female video game characters are designed to be at the largest average in build, Ellie has a wide frame, limbs that make her hands and head look comparatively small, and wears clothing that is practical first and foremost. Still, despite this, her butt provides evidence that her size isn't something she feels any shame over.
To the contrary, Ellie is incredibly proud of her body, and feels beautiful because of her size, not despite it. How do we know? Well, of course, because of her butt.
If you look at Ellie's butt in game, you'll notice that one of the few bits of flair on her outfit in game is situated there, a single solitary flower placed on one of her back pockets. Considering the rest of her outfit is so functional and plain, dungarees and a plain sleeveless shirt, she clearly wants to draw attention to the butt, and it's not tough to see why. Her butt is functional, allowing ample cushioning from bruising when sitting on the ground doing repairs for hours on end. Her butt is large enough to give a great handful to hold on to, and springy enough to make hugs comfortable as heck.
Ellie has a lot of junk in the trunk, and she knows it. She's a fat girl, and she's loving herself for it. She took one of her largest features and accentuated it with a flower, demonstrating to the player that while she is a big gal, she's not just content with that, but proud of it.
Ellie's butt flower in Borderlands 2 is the epitome of body positivity at a larger size, and informs us greatly about how she feels about herself as a character. In a world where larger female characters are so rare, the butt of this character shows us how to properly make larger ladies in games that are not just the butt of the joke.
Skull Kid – The Legend of Zelda: Majora's Mask
In the Legend of Zelda: Majora's Mask, the primary antagonist is a character called the Skull Kid. Emboldened by the dark magic of an evil mask, this impish child of the forest spends three days trying to cause the moon to crash into the earth, with the intention of destroying all life on the surface. However, despite these dark intentions, Skull Kid is ultimately a sad scared child, and one of the key ways we learn about this early in the game is via his butt.
To detail a little of the Skull Kid's story, a lot of his anger, resentment, and sadness are fuelled by loneliness. Previously befriended by a series of giants, when the giants had to leave the world awaiting a time they would be needed, the Skull Kid felt betrayed and abandoned. This is what is drawn out by the dark mask he wields, but it's not the entirety of the character, at heart he is still just a child who wants to play and have fun.
When Link first reaches the game's observatory, it is possible to spot Skull Kid standing atop a large tower, and when he notices you've spotted him, he turns around and shakes his bottom at you before running away.
This simple moment is hugely telling, because it demonstrates early on to the player that Skull Kid is still childish and immature, and that he is still ultimately a kid at heart. This is important, as it's one of the few early indicators that there is hope for redemption for the character, and that perhaps he's not a villain who needs to be killed or imprisoned for life in some prison dimension.
Tracer – Overwatch
Tracer, Overwatch's cover star and time travelling magical lesbian pilot, has an impossibly deep butt crack. While most video game characters with deep looking butts achieve this by basically painting premade shadows onto the butt, giving the illusion of shadow, albeit a shadow that doesn't move or change in response to lighting changes, that's not how Tracer's butt was achieved.
The primary cause of Tracer's plump backside is an inhumanly deep buttcrack. In fact Tracer has a butt crack so deep that regular humans could not possess similar physiology and survive. Such a crack would inevitably interfere with organs and the body's structural integrity.
As a result of this bizarrely deep posterior, Tracer can be put in literally any pose, under any lighting, and her butt will still cast a shadow implying depth, plumpness and tautness. The way Tracer's bottom is emphasised in any situation is a genuine feat of engineering.
On top of that, there's more. Another aspect of Tracer's butt that plays a big part in its eternal visibility is the fact that her outfit is either impossibly tight or glued to her ass cheeks. If you look at her bottom head on, you'll see that rather than finding a natural resting point between the cheeks, the fabric of her costume follows every contour perfectly in a way only achievable with some kind of skin safe costume glue.
So, why was it important that developer Blizzard give Tracer such an exaggerated butt? Well, there's a narrative justification in one of the Overwatch narrative short films. Tracer is a true butt aficionado.
As shown in the original cinematic trailer for Overwatch, Tracer when in combat with Widowmaker warps past the character, then pauses, and takes a moment to look back and admire her butt. This isn't a logical or safe thing to do in the heat of battle, so there must be a narrative justification for her action. There is, and it's that Tracer loves butts. She loved them enough to pause and admire Widowmaker's, and she loves them enough to glue her outfit into the deep recesses of her infinitely deep butt crack.
Miranda – Mass Effect
Introduced in Mass Effect 2, Miranda as a character is designed to be flawlessly beautiful. From her slender figure and blemish free skin, to her muscle tone and plump butt design, Miranda is designed to be literally perfect.
There's an in game narrative justification for this, which goes a long way to explaining why her in game butt needs to be quite so unbelievably large and yet perky. Miranda is the result of parents investing in genetic modification.
Miranda's parents in the Mass Effect series engaged in genetic editing before their daughter was born, with the aim of creating her to be perfect on every level. She's smart, creative, confident, and yes she has a body that's crafted to be perfect. This is in universe a source of distress for Miranda, as the expectations placed upon her become too much pressure to bear, but as much as she attempts to escape the fate laid out before her, she's unable to completely avoid being reminded that, deep down, she's a science experiment expected to never fail, with the pressure that entails following her forever.
While many may just look at her perfect butt and see something to oggle, a true butt expert looks and sees a tale of impossible expectations placed on a woman who, at the end of the day, is only human.