There are almost no requirements, however the majority agrees with the army being Lego is the best it can get, doesn't matter the size.
( ͡~ ͜ʖ ͡°)I have a very limited brick pool as well, so I just make due with what I have. Don't be afraid to make ragtag PMC/Barbarian Raid Team/Deathmetal Band/Sociopathic Boyband/Occultist SJWs you don't need a super proper, organized "army". You can make changes to them overtim-
excuse you
even people can be used in a brikwars batle.
Oh yes and Cats.