Keeper!Sans wears a space patterned parka with the 6 human souls running up his sleeves and black fingerless gloves, he often wears pink canvas shoes. the fur of his parka sticks up giving him a very fluffy look. he switches between a white one piece or a white turtleneck one piece both have the soul of determination on the chest.
Being that his true form is that of an infinite black mist he summons bone like platings to contain himself so he does not spill out all over the place. These platings never connect properly, due to the often rushed summoning of the plates when talking with others, especially around the head thus the nickname Craghead. These visible sections show his true form underneath. he also has 2 sets of wings one on his lower back and one between his shoulder blades but he rarely shows them in public
Keeper Sans has much of the same personality as Classic Sans. One major difference is his severally lowered amount of empathy and lack of trust for other Sanses or those filling the Sans role. He lacks empathy due to the fact he absorbed his Chara's Hatred and it is constantly eating away his control.
Along with the normal Sans abilities these are the powers he gained from the human souls.
Nigh-Invulnerable: Sanses actual body was destroyed when he absorbed the 30 human souls but he was able to retain life as an inky mist. In his mist form he is completely incapable of being harmed. but when worn down sufficiently he can be harmed.
The Gaster Disaster: Sans has the ability to summon so many Gaster Blasters that it can blot out the sky. And when fired its beams can be minipulated via Sanses thoughts.
Soul Phantoms: Ability to project any of his 31 Souls across time and space to speak or fight for him.
Reality Alteration: basically the power to control anything. Examples would be turning air into water or turning a person into an entirely different person. This is his least used power because it leaves him tired to the bone.
Multiversal Travel: Ability to hop between universes at will.
Soul Creation: Ability to create souls of any trait, but they can only inhabit soulless bodies
Reincarnation: Each time he dies he his mist scatters and recollects into an unbreakable heart shaped red diamond he can only be revived in his home universe where his mist reconstitutes
Soul-Merge: A new power he developed that allows him to merge his souls with another being granting them his godly powers. he has no control after a merge except to unmerge as well as the ability to appear as an astral projection of himself.
The Devil's Keeper: When Sans revived his Chara he extracted their hatred for humanity and absorbed it. When he experiences high levels of extreme negative emotions he becomes The Devils Keeper, a ten foot rage machine with sharpened teeth and black bone wings from his lower back. In this mode he attacks any he sees. The only way to subdue him is with high amounts of Kindness. Devils Keeper isn't a product of Chara's hatred merely a demonic entity that latched on due to the hatred.
- Holy Weapons: Sans is suseptible to holy weapons when in his Devils Keeper mode or his Hatred mode
- Chara's Hatred: due to his ludicrous amounts of power, the hatred Sans absorbed from his universes Chara slowly builds causing him to take on a more demonic apperance and demonic attributes. At its peak he will actually become a demon, losing most if not all his positive emotions. The only solution to this problem is for Sans to spend time with his universes Papyrus which reverses the effects.
- Fear of Inadequacy: He has a morbid fear of being unable to assist those in need. this fear stems from the fact that although he has immense power he does not truly understand how to use them.
- Monophobia: He suffers from the fear of being alone knowing he will far outlast his loved ones.
- Stunted Powers: Having Absorbed the 30 human souls as he was turning to dust the scale and power of his abilities have been severally stunted.
- Multiversal Singular: Being that he is each alternate version off himself the different Keeper factions are constantly at war in his Mindverse leading him to randomly change into different Keepers each with wildly different motives and even different powers.
Keeper!Sanses story follows that of a genocide run up until the point where Frisk kills Papyrus. After witnessing Frisk's brutality Sans retreats into his lab bent on fixing his machine, which is revealed to be a device meant to contact and interact with the greater multiverse. By the beginning of Frisk's fight with Undyne Sans has finished repairs and contacts 4 parallel universes in permanent pacifist endings. He pleads for each universes 6 souls to try and counteract Frisk's reset ability. He is given each universes 6 souls with little hesitation. By the time Frisk has finished their fight with Metatton Sans has returned aquiring his own universes 6 souls from Asgore.
As Sans enters the judgement hall so does Frisk, wearing a twisted smile. Sans dispenses with all formalities stating that this has happened to many times for him to give out motavational wisdom. Only when he is on the verge of death does Sans reveal his trump card. absorbing all 5 sets of human souls Sanses body erupts in light and turns to dust. Before Frisk can step towards the throne room the hall is engulfed in black as 2 blazing blue eyes stare down at Frisk. The fight recomenses with Frisk being handely defeated. Sans own powers far surpasses Frisks reset power and he absorbs their soul.
In the aftermath of the battle Sans takes on a more... Sansy form, and sits with Asgore and Flowey in the throne room. They discuss the future and Sans comes to an ephiphany. If he had been able to so easily break into the multiverse what was stopping less reputable types from doing the same. Testing his new powers at Floweys prodding Sans effortlessly returns life to every being in the underground, even Frisk comes back with tears rolling down their face. A bewildered Flowey grows into an even more bewildered Asriel. With a snap of his fingers Sans shatters the Barrier and 6 human children pop back into existence. Sans returns to his home were an exstatic Papyrus is shouting about his father. A teary W.D. Gaster sitting on the couch. After a heartfelt reunion Sans fades into the multiverse, but not before a child with red eyes awakens on a bed of yellow flowers.
As he floats in the space between universes Sans is confronted by the custodian of the multiverse Ink!Sans. After a long talk about everything there was to know about the multiverse and after Ink drew a picture of Sans they parted ways the job of Gatekeeper of the Multiverse bestowed upon Sans.
- Keeper Sans is known as a Multiversal Singular which means he comprises every alternate version of himself Ex. Keeperfell Sans, KeeperSwap Sans and so forth, and switches between them frequently.
- He generally distrust others who fills the Sans role in their universe due to them largely being the ones to access the multiverse to disrupt order.
- His other form Devils Keeper is a completely different entitiy Sans has incorprated into his being.
- When not on "duty" Sans can often be found in Outertale.
- He Hates Swapfell Sans.
- Has a crush on Altertale Toriel but refuses to admit it.
- when he changes into a different version of himself so does his home universe.
- During a visit to Mentaltale , Dr. Gaster diagnosed him with all the symptoms of multiple personality disorder and made a suggestion that due to his immense power he may actually bring his alternate selves into reality.