i could go on an entire tangent about why i dislike grounder "culture" but for the sake of everyone's sanity, i'll skip that.

i. NAMES

the grounders are almost all named after monuments/landmarks that existed in america, most often in or near washington, D.C.

examples:
lincoln: lincoln memorial
lexa: alexandria
ontari: ontario
emori: memorial (uncertain of which one)
nia: niagra falls
roan: roanoke
otan: botanic gardens
costia: anacostia river

ideas:
arli: arlington
tagon: the pentagon
thea: ford's theatre
ortra: national portrait gallery
ren: renwick gallery
aytor: claytor lake
galla: gallaudet university
pavil: old post office pavilion
nova: nova scotia
arlo: charlottesville
enan: shenandoah river
(if you decide to use any of these, please give me credit!)

ii. LANGUAGE

the official grounder language is called trigedasleng (also called "trig"). it was developed so the mountain men couldn't understand their language and is a rough derivative of modern english.

names in trig are spelled with the phonetic alphabet, meaning exactly how they sound.

examples:
bellamy: belomi
clarke: klark
lexa: leksa
octavia: okteivia
lincoln: linkon
nyko: naikou
gustus: gostos

my characters, fallon and caleb, would be falon and keilob

i get a lot of questions about where i get my translations of trigedasleng from. the answer is trigedasleng.info! they have direct translations from each episode, a dictionary, and grammar. when i want to construct my own sentences, i usually look up individual phrases and piece them together using the grammar rules.

examples of my own stuff:
Osir nou get in chon daunde bilaik!: We don't know who that is!
Klir ai of!: Let me go!
Yu hon yu in osir sisplei: We're here to help.
Osir na wich em in: We can trust her.
Disha laksen. Shof op: This will hurt. Be quiet.
Bak op, Skaikru: Get away, Sky Person.

in season 2, it was revealed that only the warriors speak english, but i guess that was thrown out the window later on lol

iii. LIFESTYLE

fighting??? death??? bloodshed??? idrk what else to put here because all they seem to do is fight

iv. NIGHTBLOOD

the grounders who have nightblood are presumed to be "special" and are usually in line to be commanders. the black blood originated when becca pramheda went to earth and injected it into the survivors she met to help them survive the radiation.

known nightbloods:
becca pramheda
lexa
aden
luna
ontari
clarke (synthetic)
madi

currently, the only two living nightbloods are clarke and madi

v. COMMANDERS

the commander is chosen after a conclave in which nightbloods duel to the death or escape (like luna did). the translation into trigedasleng is heda, after becca pramheda, the first of the commanders.

the rulers are given absolute authority over the twelve clans, with help from ambassadors. they are also given guidance with ALIE 2.0, also known as the Flame, which houses the spirits of previous commanders as well as their memories (as explained in seasons 3 & 5). only a nightblood can survive with the Flame in their body; any other person will basically melt from the inside (like emerson).

known commanders are:
becca pramheda
lexa
ontari (by force & without the flame)
roan (briefly)
octavia/blodreina
madi

the grounders are basically willing to follow anyone who has the flame, as stated by clarke in season 4 with roan and proven by gaia, bellamy, indra, and madi in season 5. (a nightblood with the flame is a double whammy.)

vi. CLOTHING

typical in trikru style:
-armor
-weapons such as swords, knives, bows, axes, etc. no guns
-mostly all black/very dark grey
-bulky clothing
-usually several layers
-black warpaint
-hair braided back, for both men & women
-tattoos (mostly sharp & geometric)

flokru:
-some type of netting
-very loose, tattered clothing
-lots of blue, aqua, green, etc
-jewelry (beads, leather, shells)
-loose hair as opposed to trikru braids
-usually no weapons (as they are peaceful)
-barefoot sometimes (as luna is shown here)

azgeda haute couture:
-grey, white, and black color scheme
-fur-trimmed coats & armor
-white warpaint, sometimes with black around the eyes for some reason so they look like pandas
-lots of buckles and metal clips
-white around edges of clothing to look like frost
-generally super heavy clothing because they live so far up north (likely the remains of canada)

(^this picture is so funny to me i can't stop laughing jakskslalmdwm)

that's it! if you have any questions, i'll try to answer them to the best of my ability