How are GW opponents selected?

Benr3600

Is it based on power, or arena ranking, or both, or something else entirely?

Scoregasms

There's been a few threads related to this topic, short answer is, nobody truly knows unfortunately, lol. But good to read up on some theories folks have come up with, this thread can be a good start:

https://forums.galaxy-of-heroes.starwars.ea.com/discussion/4545/how-does-galactic-war-matchmaking-work