Phew, what a list! I’ll go through them one by one. A lot can actually be rolled up into their parent abilities, as a borrower can often only exhibit one facet of them due to their weaker strength compared to the angelic source of knacks.

Physiognomy– “the assessment of character or personality from a person’s outer appearance, especially the face.”

Another ability that would help you give Sherlock a run for his money with deductions!

Oculomancy– “a form of scrying where the diviner gazes into the questioners’ eyes and reads the reflections.”

This would likely be linked to a form of telepathy where the user needs the eyes in order to focus their ability.

Echolocation– “the location of objects by reflected sound, in particular that used by animals such as dolphins and bats.”

Can you just… imagine a borrower… screaming their head off at the house around them. Some human somewhere is going to wake up with nightmares because someone’s been screaming all night in the walls.

X-ray vision– “the ability to see through physical objects at the discretion of the holder of this superpower.”

This ability definitely rises from the angelic Grace instead of the user. It’s well known that angels can reach their senses beyond their physical form, and sight is no exception.

Icicle touch–

Likely some form of controlled heat conduction, draining away the heat in the person receiving the touch. Or, conversely, making the borrower too cold to touch.

Astral projection– “a willful out-of-body experience that assumes the existence of a soul or consciousness called an “astral body” that is separate from the physical body and capable of travelling outside it throughout the universe.”

Astral projection and dream walking are two of the abilities that one might not realize they have at first, but once they do it can be a good way to explore the world outside of their stifled, hidden homes.

Camouflage–

This fits snugly between the reality warping ability and enhanced stealth, quickly creating camouflage for themselves or for the entrances in and out of the walls that they need.

Unbreakable bones–

Another way the protection ability can work, but they quickly find that unbreakable bones don’t always mean they can’t bruise, as their muscles can only take so much damage.

Pencil/ink fingers–

Like writing with their fingers? It could come in useful for when planning out their next project in the walls, though most borrowers don’t write, and many don’t bother to learn how to read.

Shadow manipulation–

Often used in stealth. Sean does a form of this, creating shades and shadows around himself and other borrowers that cloud the vision of any humans trying to look at them.

Smoke/dust manipulation–

A form of telekinesis where they can only manipulate tiny particles, learning how to make shapes out of the dust motes in the air.

Zero friction skin–

All I can think of is NYOOOOOOOOM and the belated discovery they can’t slow down before they crash.

“Bottomless” bag–

If Dean wasn’t a tracker, this would be his next given ability. Even as a human, his duffel bag seems bottomless! The Doctor has this ability with his pockets, despite not being a borrower, using technology instead of angelic Grace. A form of reality warping.

Matter eating– “Able to bite through and consume all forms of matter; including that which is supposedly indestructible.”

The vore borrower. A useful ability for surviving in times of scarcity.

Omnilingualism– “the ability to understand and utilize verbal or non-verbal communication without any prior knowledge of the language.”

An extension of telepathy and mental manipulation. They would learn the communication from the person they’re communicating with as they talk.

Paper thinness– 

It’s beyond the ability of a borrower to change their shape.

Light absorption–

An extension of shadow manipulation that affects light instead.

Sound mimicry–

Especially useful if they know how to throw their voice! They can get the human to go looking for a completely different animal in the other direction.

Energy vampire– “a person who feeds off your emotional, or psychic, energy.”

An extension of empathy where the user learned how to pull the energy from someone else, an ability that can lead down a dark path if it’s used badly.

Emotion smelling–

An aspect of enhanced awareness that heightens the natural ability to sniff out emotions– something people have the ability to do but don’t often realize it. This knack makes it so they can always tell what the emotions around them are.

Dream manipulation–

An aspect of mental manipulation that centers on dreams. Probably not to the point of Inception XD 

Empathic manipulation–

One of the stronger abilities of an empath. 

Persuasion–

An aspect of mental manipulation.

Sedation–

An ability inherited from the angelic Grace. Usually requires touch to function.

Intuition–

A weaker form of prescience where the user gets a feeling that not everything is as it seems.

Terrakinesis– “the ability to control the earth, often by causing earthquakes or tremors, enough to destroy buildings.”

An ability inherited from the angelic Grace. The angel Hael admitted to being able to carve the Grand Canyon in eons past. A borrower can’t affect the earth to this extent, but it is possible that a terrakinetic user helped the borrowers in the burrow reinforce the walls and extend the passages beyond what they found from the rabbit warren it originally began as.

Palletakinesis– “the ability to manipulate paint/pigment and make the paintings real.” 

A form of reality warping that might take too much power for a borrower to maintain with a full painting. I bet Dean would have fun with it, messing with the ink marks on Sherlock’s work if he’s ever annoyed with him.

Thermal immunity–

Another way the protection ability can work, but its effects are limited in a full blaze of fire and useless in lava due to the limitations the small folk have. 

Lie detection–

An offshoot of telepathy. Hard to lie to the person who can read your thoughts.

Since Bittersweet Parting has wrapped up, bringing the second season of Brothers Apart to a close, it’s time to get in-depth with one of the more integral parts of the multiverse– the knacks each borrower is born with!

For that, we’ll have to touch on the origin of the knacks, and it all starts with Celeste, or Saraqael, as her angelic siblings have named her.

More under the cut, because this will go in-depth on the background of Brothers Apart:

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When Celeste first put forth her plan to Azazel, before the Fall, it stood in contradiction to ideas of his own. She was able to brush aside any plans of using demon blood to enhance the forms of humans, calling it a short-term and unsustainable drug that would accomplish half the goal for twice the strain on the humans. If her brother is to have a vessel, he will need his vessel to be stronger than any living human, to keep the darkness and power from overcoming them.

When she fell, her experiments and quest to prove this began, and the first humans to suffer her curse were the village of her host’s origin, including the witch Adriana, who framed Celeste as a witch to take the suspicion off herself.

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Humans under the curse received instant boons in the beginning. More than a simple hex, the angelic curse she put on them combined waves of her Grace with the natural power of a human’s soul. They became stronger, their sense heightened.

To counteract this and to keep the angels from discovering her plan, she also used this curse to shrink them to nearly a twentieth of their regular height.

Hidden from sight and discovering that humans no longer considered them equals, the small folk developed their own communities and traditions, and so the curse began its work.

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Originally, Celeste used the curse indiscriminately on both adults and children both. It wasn’t until a century had passed that she realized that while adults could possibly receive the boons she wanted– stronger bodies, stronger vessels– the amount of Grace she needed to use was multitudes higher than what she needed for children.

The children would grow into their power, the same way a tree that took in fallen Grace as a sapling or a seed would explode in growth.

By the time she curses Sam Winchester, she is an expert at the art. Giving him a minimum taste of her Grace is all it takes for him to grow many times stronger than Dean, a direct contrast to the fact that at only a few inches tall, it does him no good against his older brother.

Born vs cursed:

Kids born with the curse don’t always show signs of having a knack. Though the potential exists in every ‘borrower’ (A name given to them by one of the few humans to discover them decades back), it’s often overlooked or never manifests.

Cursed kids always show a knack because of the rapid way the curse works its magic on them compared to the slow growth of being born into it. They still might not notice, especially a knack that simply heightens their ability to slip in and out of a room undetected, but it is irrevocably always there, an advantage over the kids born small.

Types of knacks:

Disclaimer: Not all knacks have been discovered or quantified. This is an ever-growing list.

Knacks can be a trait of the borrower that’s been enhanced by the angelic Grace in them, or they can rise directly from the Grace, giving a borrower an ability seen in the angels with the exception of Flight, as they have no wings of their own. 

Borrower knacks have strict limits in power, as opposed to the angels, who seem limitless.

1. Telekinesis: The ability to manipulate objects outside of their direct reach. This can often cause a borrower to be mistaken for a ghost, moving objects in a house without touching them for a distraction. Walt Watch has taken the ability further, freezing two humans in place and later directing his power at himself to force his razor blade through Celeste’s neck despite her angelic invulnerability. This came close to burning out his knack.
2. Telepathy: Able to beam thoughts into the mind of a human, or communicate with the other borrowers from a distance without being overheard.
3. Invisibility: Though the borrower does not make themselves actually invisible in most cases, the invisibility knack allows them to camouflage and blend in to their surroundings. In Sean’s case, he can cause a cloud of distortion that hides himself and any of his friends that stand close enough.
4. Essokinesis (Reality Warping): Though reality warping seems too strong for a borrower at first glance, it tends to arise as an ability to change objects around them, often making a useless object into something useful, above and beyond a borrower’s regular mechanical prowess.
5. Pyrokinesis: The ability to manipulate fire in limited forms.
6. Enhanced Awareness: This can either enhance an already understood sense to supernatural levels, or give the borrower a ‘sixth sense,’ much like how Sam can feel if he’s being watched. His ability does not work on other borrowers, the angelic Grace around their souls keeping the perception from working on them.
7. Enhanced Tracking: Trackers, like Dean, are able to use their ability to track down their target with undeniable accuracy. There are limits, as Dean can only track down objects he needs. He is unable to apply this to people, and if he can’t conjure up that sense of need, nothing will happen. This is not limited by distance, though if he’s far from an object, he only gets a sense of what direction it’s in.
8. Supernatural Strength: Some, like Jacob, grow stronger than even other borrowers. This comes from their innate ability to turn their knack on their own bodies by instinct. These borrowers can rarely stretch their power beyond their body, but as a result, they can lift weights far beyond the limit of any others. Some borrowers only have certain parts of their bodies enhanced, giving that part a boost above and beyond even that extra strength.
9. Protection: Like the invulnerability of an angel, some borrowers are able to guard themselves from damage. They can be stepped on or fall from a high distance and receive only bruises. If you ever see a borrower ‘bounce,’ there’s a good chance they have this ability and don’t realize it.
10. Mental Manipulation: A knack that’s easily abused, mental manipulation can go from talking a human into ‘forgetting’ they ever saw a borrower all the way to digging into a person’s mind to control how they think. Highly dangerous. Adult borrowers have some immunity to this knack due to the angelic Grace, while children can be manipulated as easily as a human. Can also manifest as the ability to divert a human’s attention.
11. Time Distortion: The ability to slow down or stop time. A very strong knack that requires training to sustain for longer than a few seconds. 
12. Regeneration: The ability to regenerate wounds. Some borrowers with this ability have also been seen to extend their lives beyond the natural lifespan of their race, retaining youth.
13. Animal Empathy: The ability to form close bonds with animals. Often used on mice or rats, sometimes bats and birds. Even a few friendly spiders exist that borrowers have befriended. A strong user of this ability can even mentally communicate with the animals.
14. Static Electrokinesis: The ability to manipulate static electricity. A borrower with this ability might be seen with extra frizzy hair a lot before they realize that they’re doing it to themselves. If trained, they can zap on command and even stick to walls if they’re light enough.
15. Empathy: Empaths can sense the emotions around them, either from a distance or by touch, depending on the strength of their ability. The strongest empaths can share their own emotions with others, by force or by choice.
16. Psychometry: Able to learn facts about people or events by simply touching inanimate objects associated with them. Stronger users can do this with a glance. Learning how to slow the rush of facts and information is often a necessary survival technique for these users, so they don’t overwhelm their mind.

17. Prescience: A brief look forward in time, to parse through possibilities and see what can arise from certain decisions being made. 

18. Enhanced Stealth: A fairly common knack, borrowers with this are the best at sneaking into and out of rooms without being detected, even if the humans are up and active at the time. 

All these, and more! The knacks that borrowers use are as varied as the abilities humans have, and new ones are being discovered all the time!

Burnouts:

If a borrower pushes their knack beyond their breaking point, the knack will snap and render their ability useless. A sign that they’re approaching this point is a headache, often accompanied by a bloody nose.

Siblings:

Closely raised siblings often develop knacks that support each other’s. Sam and Dean are the prime example of this. One knows when they’re sought, while the other can find whatever they seek. 

Age:

The older a borrower grows, the longer the Grace has to work on them. This causes their knack to grow in strength even if they don’t train it. Sam notices this because he can start to differentiate between people like Dean, who are no danger to him and thus the sense he gets is ‘softer’ than someone like Gordon, a hunter actively trying to kill him. This makes Gordon’s gaze feel ‘sharp’ compared to Dean, and can cause Sam physical pain because of it. Walt’s telekinesis is far stronger than a young borrower could manage without training, able to suspend two full grown humans in the air without burning out.

Limitations:

As useful as knacks are, there are limits to what they can be.

• Borrowers cannot change their size.
• Borrowers cannot shapeshift.
• Borrowers cannot fly or teleport.

Some of these limits arise naturally, as borrowers do not possess wings like their angelic source of magic, while others are limitations Celeste worked into her spell. She can’t afford to have her experiments switching back to human size.

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If anyone has any questions, let me know!