Not necessarily done, just not sure where else to go with this. Unless we want to write some kind of story outline.

Well, we could go over possible Sub Bending forms. Or professions that could best utilize these forms.

@Zealous Gamer sorry I think I wasn't clear before or didn't understand but are shadowbenders just lightbenders who focus on bending the absence of light or benders that bend dark matter?

No. They aren't the same.

Light and Darkness are Elements in pop culture. I think you are viewing Darkness from a scientific point of view. Often times Light and Darkness are also opposite Elements. In other words; these 2 would make 6 Elements rather than just 4. It's difficult to describe. But, Darkness often is treated differently in Fantasy. Often giving it certain attributes (depending on the fiction). Sometimes Darkness can be connected to evil. Or it can be more neutral. It can even have a connection with death.

I will say that I do actually have a few threads discussing both Lightbending and Shadowbending. If you look up "Just For Fun" and go to the "post" section; you'll see what I posted there.

@Giasfelfebrehber12 and @SonoPazziQuelliRomani Have you guys checked out the "Just For Fun" threads? They have a lot of concepts covering both Lightbending and Shadowbending.

I liked the idea of a group of earthbenders who lived underground tbh. Apparently that was how Ba Sing Se was founded which gave me an idea. What if after everything that’s happened in Ba Sing Se and the EK as whole, some earthbenders believe the city of Ba Sing Se, and the Earth Kingdom as a whole has suffered from the spiritual decay and imbalance unalaq believed the SWT suffered from (likely due to the proliferation of spiritual energy weapons and advanced technology) and sought to connect with earth spirits underground as well as to withdraw from the mess, and general chaos that is the society of Ba Sing Se. So they journey to the crystal catacombs beneath the city where they plan to live connected to the earth (spiritually speaking) sadly, food would likely be difficult to come by down under meaning they would likely have to go up and scavenge for food at night when people wouldn’t see them. This leads to rumors about earth spirits running about the city at night and Avatar Korra coming in to investigate. Upon her arrival in Ba Sing Se, she doesn’t find them immediately but wants to help (in typical Korra fashion) and bc opportunity, maybe she finds one of them at night scavenging and she tries to stop them and most likely follows them and is led underground where she meets them, learns about their way of life and ideals in which she makes a pact with them. So long as they do not disturb the people of Ba Sing Se, they will be able to live in secret free of the EK government, and Dai Li (I refuse to believe the Dai Li fell apart after Zaheer merked queenie, hell, I bet they supported Kuvira) in exchange Korra helps to create a more permanent food source that can survive underground and feed their people for generations. This agreement allows for the people of Ba Sing Se to live their lives with no knowledge of the “underground” (I could come up with a better name given more time, energy, and less on the spot writing) and vice versa. However, i imagine after generations living underground cannot come without problems as many if them would probably not have the best opinion of people above ground, and their culture could be pushed to earth’s extremes of being stable and unchanging. This in it of itself could be a major source of conflict for the Avatar after Korra if left unchecked. Maybe the next Avatar is born in this community and longs to venture above ground which could be frowned upon by their people and hopefully be resolved in this Avatars lifetime.

Wall of text.

Here is a question: if Light and Shadow were to be added; what would the new Avatar Cycle look like?

I think if Light and Shadow were added, it would pose a bigger question of how an element is "added" in the first place. Does "adding" just represent when Lion Turtles gave people the ability to lightbend/shadowbend?

If so, I think there are two possibilities: fire, air, water, earth, light, shadow (which would be correct according to lore, seeing as the avatar cycle started with a firebender) or: air, water, earth, fire, light, shadow. The only reason I could see the latter happening is because the show originally began with Aang, an airbender and in away he represents the first avatar since he's the first whose story we (as viewers) see. Looking back, the first does make more sense, but let me know.

The only reason why I think Light should come before Shadow is because that's usually how people refer to it- as in 'light and shadow' rather than 'shadow and light'.

@Zealous Gamer The only reason why I asked was because if Shadow does represent the fantastical idea of Darkness, should it still be called shadow? (granted, 'darkbenders' does sound kind of weird, and 'light and shadow' sound better together)

I also checked out some your other "Just for Fun" threads and they all seem really interesting & well founded! Are you thinking of putting all of it into one larger post, or blog post (not sure thats what they're called but the kind of posts where it's your own page or smt?)