Introduction to Mana
No one knows where mana (Pronounced "mah-nuh" in the PTverse) originated from. Mana is essentially the universe' "secondary air" and method of performing supernatural feats such as conjuring items that are otherwise unreachable, magical spells, near-instant healing, numbing substantial amounts of pain, deflecting or destroying incoming bullets and even having their bodies destroying harmful or useless substances within their bodies. (Assuming it's not mana-related) Although "This Crazy World" claimed that only living creatures who believe in the Christian God are said to be given mana, as of 2015, the series as well as that rule has been retconned. Now all one needs to do is have a religious belief to obtain mana, regardless of how good or bad their personalities are. Regardless of how augmented the body's defenses are with mana, it becomes impossible to live without it once it becomes a part of the individual. This dynamic has decreased the death rate for worlds that received mana later than others, but the methods of killing someone became a lot more elaborate and gruesome in the process. It is worth noting that Earth in the PTverse received mana December 21st of 2012 while the more fantasy-oriented worlds like Accelerando usually had mana from inception.
How Mana Works
It acts primarily in 4 ways: Defensive combat, offensive combat, healing and internal cleaning, and the ability to "sync" to mana-compatible technology to enable a more streamlined living experience.
Although it is largely unknown for the characters, the potential of one's mana - particularly on Earth heavily depends on how much strength they needed and/or wanted and why prior to receiving their powers. The more supportive personalities received powers related to helping others as opposed to raw strength. Inversely, someone with tremendous strength most likely desired more of it before receiving mana. However, in worlds where mana was always present, one's strength heavily came from their parents and how well they could hone it.
Mana becomes stronger and more durable when it's used, much like muscles. One's physical shape does play a small role in how potent their mana is, but it's up to the user to fortify and augment it via physical training and fighting. The scientific reason behind it remains largely unknown to scientists across the universe. It's argued that it's because mana acts as a sort of 'omni' element that it can compliment humans' daily needs and growth so well.
Fighting With Mana
Mana's main priority is to protect its host at all costs. Mana is mostly concentrated around the heart, neck, and brain but will focus on other body parts if needed. It will heal, shield, or even violently shove the host back in order to take minimal damage during a fight. Half of the time, it's actually a host's mana that injures and hurls a character away rather than any magical attack directed at them. The more potent the enemy's mana, the more fiercely the host's mana reacts to keep the otherwise fragile body safe. Thanks to the pain being minimized, a character with mana can take a lot more stab wounds than they normally would, but every character has a limit. The more damage they take, the more mana they lose, and once they lose all of it, they cannot live. A character can also instantly lose their mana if their mana cannot withstand a "one-shot" like a decapitation. These cases are rare however as mana tends to be quite durable. It is far more likely that one's overbearing powers will simply render its prey unconscious after a single blow instead.
Healing and Augmenting with Mana
Oftentimes mana loss can be reduced and even reversed thanks to the ability to heal and increase defenses for others and oneself. Mana will begin to heal most injuries for its own host immediately, though the process can be expidited if they focus their mana on healing. However, most children cannot heal themselves or others until around the age of twelve, so whenever they're involved in a large scale fight, they're usually given the role of augmentation or supporting spells like shields. When augments are given, it can boost speed, strength, endurance, and even accuracy. People who are new to combat need to touch or grab their target if they wish to heal or augment the individual, however it has been proven that after some experience, they can start "buffing" (slang for augmenting) from a distance.
Weapons & Spells
Most characters have at least two to three weapons infused or "synced" with their mana for different occasions. Much like casting a spell, each person can "summon" an item - usually a weapon - to bring to combat without mana considering it an offensive or defensive decision. This will make said equipment disappear from where it's at and reappear in the hands of its owner at any given time. This is in large thanks to inventors in each world like Huron Vindili from TCW and Polka from Mesto Accelerando (MA) coming up with ways to "sync" one's mana to their property though the integration of science. Depending on the individual, they can usually also cast elemental spells that work to weaken or sometimes penetrate the foe's mana. Due to how protective mana can be for everyone involved, bullets and spells are usually there to chip down one's mana so a sword, which is universally considered the most potent and reliable weapon in large thanks to how much more mana it can hold, can finish the job.
The most dangerous and terrifying use of mana. When the host becomes too emotionally strained with sorrow and anger, their mana violently reacts by amplifying its power, but in doing so, the host becomes a slave to the emotions that caused the Mana Break to begin with. This blurs the line between friend and foe for everyone and more often than not, causes unwanted death for all sides involved. It's heavily looked down upon and a social taboo to get to that point, so instances of it are rare, and in Mesto Accelerando, the ability to even use a Mana Break has been taken away by Polka's technology from all but Sonatinas.
One of the most interesting aspects of mana is that the closer one gets to death, the more useless healing becomes. The dying can be spotted by bright orbs of light slowly escaping their bodies as their mana prepares to "clean up" the body as best it can before the rest of the mana flies away. It is also very common for a death to happen too soon for the process to begin prehand. In those cases, the mana simply hurries up and cleans up the body before leaving the host through countless orbs. "A night lit from the remains of the dead. Truly a terrifying sight." -Yadav, Sonatina from Mesto Accelerando