I was wondering who all they were before I start on my first major fan fiction. Who anyone care to help?

Noxians

Talon
Katarina
Sion
Urgot
Cassiopeia
Riven (Not modern Noxian but still loves Noxus)
Swain
Singed
Warwick
Vladimir (lives close to Noxus)
Mordekaiser (not really Noxian, but lives there)
Shaco (same case as Mordekaiser)
Darius
Draven
Annie (Parents from Noxus)
LeBlanc

Demacians

Fiora
Jarvan VI
Garen
Lux
Galio
Poppy
Xin Zhao
Shyvana
Sona
Vayne
Galio

(I think thats all of them, I may have missed a few of the Demacians because I play mostly Noxian champs)

Forever Strong

Here are a few links that will help you:
Noxus
Demacia
Zaun
Bandle City
Bilgewater
Freljord
Ionia
Piltover
Enjoy the read

Varus just came out so i think ( i know ) he is in Noxus group

Varus is Ionia. He kinda wants to slaughter all Noxians.

You missed LeBlanc from Noxus.

Also although Riven is technically from Noxus you might wanna pay attention to the guilt thing she has going on about their military tactics etc.

Ain't Vayne born in Demacia?

Pantheon is Rakkoran and lives on Mt. Targon.