Is this a cheater?

With the limited information you posted, it’s difficult to say. There’s off meta and 2shot strategies for a lot of teams, and omicrons/DCs can make a huge impact.

Whatever you do, don’t post ally codes, it’s breaking forum ToS.

It would probably be best to take your questions to the “to catch a cheater” discord and have the big brains in there help analyze the fight and see if it’s plausible based on more detailed information.

I did manage to beat him, but only because he set some weak defenses, and i could use one character. He’s got about 3 mil less GP as well.

"Winterwolves;c-2436904" wrote:
You can check your history on swgoh.gg in a few days time to see what they did.

This. Speculating with limited information is pointless.

Wait until History is out and see from there.

"TitoJackson84;d-265491" wrote:
Opponent only has Jabba, slkr, and JMK for GLs. His jabba is on defense. He got a full clear against Rey, slkr, jabba, malgus, starkiller. I can post both ally codes

I'd use Starkiller against Rey, SLKR against Jabba, JMK against SLKR, JKR against Starkiller, JKL or GAS against Malgus.

You can check your history on swgoh.gg in a few days time to see what they did.