My friends shilled this game to me hard for years and I finally picked it up on sale. It's downloading now but I have third world internet for the time being so it's going to take a while.

What am I in for? I was told to also buy for the first two games because I guess I get the playable factions from them in the third game too? Is the DLC for the first two games the same? Is any of the DLC worth it?

I've never played a Total War game before.