Also, I think this would be a good time to explain about the new modes recent put into the game, with the 1st one being Rival Domains.
This mode plays somewhat like a usual Fire Emblem game, with you managing a team of units, battling the opposing team, and trying to capture the enemy base. The map is also slightly larger. These maps will happen once a week with different levels of difficulty and rewards for completing them.
You build up a team of units, up to 20 in one brigade, and you can use the main unit each of your friends use. So you can mix and match however you like. The units with the green hearts are your friends' units.
Once you're ready, you then start the map and try to get the highest score possible, from KOing enemies, capturing camps and fort, and doing bonus challenges. There is a time limit though, you have 10 turns to either complete the map, or get the highest score possible.
And that just about covers Rival Domains. And yeah, this makes more use of your friends' list, haha.