I'm hopeful I can turn the lore parts into an encyclopedia or textbook of sorts when I sort myself out. They will be posted into later parts of this story.

Questions from Vainel:

1) How did runes come into being?

All Karma's magic stemmed from celestial energy, from celestial showers resulting from the planet's orbits around the sun. All magic started in the First Family, who had twin girls born with magic: Karma and Hanna. One was blessed with bringing magic (summoning), the other with giving magic (celestial). They could never get along and were always at each other's throats. When they turned eighteen, they were exiled to either end of the country, later split into the countries of Karma and Hanna of today. Their magic diluted over time. Karma had unlimited potential in celestial magic, which could link with the elements, bond souls to bodies, and alter physical states around her. At the end of her life, Karma decided to split her magic to share with humans, allowing them to prosper using her celestial magic. Humans later harnessed the traces of her celestial energy into rune, burst, and flash magic.

2) What are the other countries like?

Hanna is the northern neighbouring country to Karma, separated from Karma by treacherous mountains, and uses black summoners' dust to summon creatures from a different realm. During the story, the ruling king, Mephis Tophalis, dies, and his son Fautos Tophalis ascends to the throne. Their lands are desolate and frozen and their people tough and determined. Demon summoners usually begin as a young child, found to be able to communicate with nature's creatures, and is then sent on a pilgrimage around Hanna to learn the language of all the creatures, completing the pilgrimage in Acrise. This respect and understanding of life at the end of the journey allows them to communicate and control the demons they summon. Unfortunately, repeat occupancy of Acrise made pilgrimages incomplete and summoning unstable, taking away valuable arsenal of Hanna.

Moakai is the country to the east bordering Karma. This is the country Seiren was banished to after she was tried for treason. A desert to the east separates Karma and Moakai. Moakai is home to  travellers and hunter-gatherers who survive dry conditions through constant moving for lush lands. Long stretch of desert prevent them from wandering into Karma. Native animal population has a tendency to be murderous and venomous.

Teirrin used to be a country that lay in the southwest of Karma. A magical war between Karma and Hanna about 2000 years ago resulted in devastation of the lands there, leaving a hazardous wasteland and a small collection of survivors. The Teirrinese had attempted to sacrifice that country to recreate celestial magic with primitive research, and failed. Cronin Sallows, the king's mage whom Karis Bonneville replaced, subsequently got hold of their research and developed it further. Rashira Miracle, the second Miracle monarch, invested in mages to create the magical border at Teirrin about 1700 years ago to prevent the wastelands from spreading, earning alliance of the survivors.

3) What are the different types of runes and how are they different? What about burst and flash magic?

Images are available on my Facebook Author page (click via my profile) -- I will polish them at a later date.

Magic in general

Rune magic: requires drawing of runes to summon energy. Can be drawn in any medium onto any medium, but effects may be unexpected if not on traditional chalk and paper. Powerful but time-consuming to create. Runes can be primed and sealed onto ceramic tiles and used (one use) by laymen. Little limit in type of media it affects, works with most materials.

Burst magic: magic linked to gestures and concentration on the mage's behalf. Power depends on user and concentration. Element-based (Fire -> Wind -> Water -> Earth in difficulty) but has limitations in potential depending on user. Easiest to learn initially, difficult to use on regular basis. Requires emptied brain and no emotions.

Flash magic: extreme burst magic to deal excess damage in a split second. Massive collaterals and require great control. Requires one surge of great emotion. Usually one type of element or effect per user, genetically pre-determined.

Fold magic: utilises paper. Folds infused with magic dictate what they can do. Created by Loren Rummage as a quirk, but never got further funding for development as deemed 'unusable in combat' by Council of Mages.

Runes

Red (physical energy -- accelerated particles)

Needs an outlet to direct energy

Sigil can alter direction of outlet

Intercepted lines help generate physical energy

With violet: result in controlled movements of target

Orange (fire, heat -- even more accelerated particles)

Quick and easy to draw

If outlet is used, can direct flames; otherwise will burn on the spot

Utilises incomplete shapes to generate heat energy

With violet: alters fire and heat properties

Yellow (light, illusions, blinding -- excited electrons)

Simple to construct if demands are low

Mages are taught that light runes must always be symmetrical

Easy to draw with modest effect

Simple, does not warrant locks unless requiring modification

The more intersections, the brighter the light

Green (healing, altering organic matter)

Works with gradients (dots along its lines)

Allows magic to lock with life energy like chaos magic, but limitations depending on user ability and recipient acceptance; typically weak unless layered on top of each other due to complexity of human body

Symmetrical gradient distribution allows even healing across the circle; non-symmetrical provides focused healing

Limited to within physical capacity of the body, e.g. can heal an amputated leg into a stump but not a new leg.

Intricate and time-consuming.

With violet: unnatural healing that results in death of subject

Blue (electricity -- excited free electrons)

Bursts of electricity

Uses non-ending lines to generate electrical energy

Difficult to construct due to complexity of shapes (so King's states)

In reality, little variations needed for same effect. More crossing lines powers rune more, like with red runes

Most important aspect is ensuring circle locks present in six- or eight-sided runes to ensure user is safe

Power can be difficult to predict.

Indigo (illusions, mind control)

More artistic, like sketches rather than shapes

Dependent more on user than the actual design of sketch

Requires concentration from creator during whole time of activation

Violet (physical modifications of inorganic matter)

Most recognisable for overlapping designs

Works best with a lot of locks as can easily overshoot

Silencing rune (punishes target if they disobeyed certain rules); tracker rune (traces target, usually using residual magic or blood, if modified can also show old magic usage); nullifying rune (cancels out magic within an area for a limited time)

Most difficult to do, most potential and variety, can easily go wrong.

From adrianzoetifa

4) What happened to the other mages and where are they now?

This list is from the casualties of the last battles of Rune Mage of the named mages who made it. If there is a sequel, the alive outcomes may potentially change, but at the time of writing, here is how I planned for them to be:

Dead list: Maura Woodbead (died of organic magic); Tesla Relish (died of flash magic injuries by Domic Butterworth); Domic Butterworth (died of flash magic injuries by Tesla Relish); Karis Bonneville (died of flash magic injuries by Rowan Woodbead/died of organic magic); Rinoa Gruger (died of magic exhaustion and blood loss).

Alive list:

Tahir Portendorfer: continued to happily fly solo but was never granted tutelage of students again per Council of Mages decree.

Bellamy Southwark: became chief advisor, alongside Kommora Haigh, to King Bolliver Woodbead.

Azriel Edevane: gained full mageship after two more years under a different mage as Southwark had taken on full advisory role. Then withdrew from active duty to become full-time tutor at King's Academy of Magic.

Halen Ashworth: withdrew from mageship after losing Tesla Relish and vowed never to use magic or affiliate with mages again. Returned to her family's metalwork company and lived as a normal human.

Kommora Haigh: became chief advisor, alongside Bellamy Southwark, to King Bolliver Woodbead. Remains sharp-tongued as ever and still deadly with a chair. Part of the revision of mage duties regarding duties to war.

Rowan Woodbead: took a hiatus of a year from mage duties due to loss of family and trauma and took a phased-return to full mageship. Became a strong ambassador against conscription of mages for war.

Seiren Nithercott: trialled for unethical research and indirect assistance to casualties. Sentenced to 6-month mageship suspension after being granted full mageship. Completed community service in Cliffe to assist management of toxic wastelands and then became the assigned Mage to Finberry. Made up with her childhood friends, the Feblands.

Kristen Harred: trialled for treason, mass murder, conspiracy against the kingdom. Sentenced to execution by beheading. Execution not yet carried out.

Zor Jarsdel: trialled for treason, assistant to mass murder, conspiracy against the kingdom. Life sentence with no chance of parole in high security beneath the Council of Mages.

Madeleine Harred: underwent an accelerated course at King's Academy of Magic after failing her probationary test (as she didn't have any practical experience with using magic, although Seiren argued that Madeleine had essentially attended every single lecture and session with Seiren during her six years at King's) and graduated after a year with distinctions. Attached to Willem Dankworth as probationary mage with an aim to become part of peace ambassador between Hanna and Karma.

Hadrien Tumbler: the forgotten probationary mage who was under Loren's tutelage. Completed mage training under Kane Temples.

Colm Hatman: retired from role as burst mage and became a tutor at King's Academy of Magic.

Willem Dankworth: took on Madeleine Harred as trainee. Became peace ambassador between Hanna and Karma, based in Acrise.

Kane Temples: took on Hadrien Tumbler as trainee.

From VigneshR6

5) Is Maura's spirit alive in Madeleine?

Unfortunately, no. It took too long between Maura being hit by organic magic to when Seiren got there; the soul was already gone. This was the same fate Madeleine would have met if Seiren hadn't gotten there in time six years ago. This was the same fate Loren met, but at the normal rate; hers was buffered because of the remains of chaos magic within her body and so she took longer to die. Which begs the question: if Seiren had been there to sketch that rune that ties Madeleine to the necklace and power it, could she have secured Loren's soul before she passed on?

Yes. Yes, she could have.

And transplant Loren's soul back to her own body?

Given the right circumstances (bear in mind a fraction of the city died to catalyse Madeleine's transplant and in exchange for all of Kristen Harred's magic reserve), yes.

From Unreallyreal

6) Now Seiren has taken Kristen Harred's power, is she one of the most powerful mages ever?

Kristen's power got used up in exchange for transplanting Madeleine when Seiren used chaos/celestial magic (catalysed by the sacrificed souls in the first pulse of Kristen's organic magic rune), so it's all gone now. Or at least, Seiren's access to it anyway. I haven't really decided, but if Seiren has access to all of Kristen's powers it would make her too OP'd and that's boring... but having some remnants of Kristen's magic in her may make good sequel fodder.

From thesilentshadow

7) Is that all the chaos magic gone, now?

No. Seiren is the only person in Karma with access to chaos/celestial magic. Parts of her magic reserve has been used up when she healed Rowan in Acrise; Kristen's reserve was used in exchange for transplanting Madeleine. But Seiren's use of magic in general remains, which includes her firework flash magic.

From Jarinrifa04

8) Who saved Seiren in Chapter 26?

At the time of writing that chapter, it was meant to be King Pollin making his second stint in getting Seiren out of trouble (Danaway being the first); unfortunately the opportunity to bring this up would be when Halen gets involved again and she wasn't seen for half a book later -- and I forgot about it.

Thinking back now, though, it seems logistically difficult to have Pollin flitting around Karma just so Kristen can keep Seiren's ass out of trouble, so I think when it comes to editing again I'll just have one of the king's mages stepping in instead.

9) What happens to Acrise now?

There's ongoing negotiation for joint ownership of the place currently but given Prince Fautos of Hanna is a bit crazy and bloodthirsty the situation is a bit fragile. If the timeline for the sequel (whenever that materialises) fits, this will be addressed.

Further questions, please post below and I will edit this chapter with answers.