I want to build a team around the Magus to pit against Infinity Watch.

I'm thinking of using several alien race generics to represent members of The Universal Church Of Truth including possibly Saurian Troopers, Korg and Miek and maybe a white Martian.

I'm also thinking of using girly Loki as his ally, just to play the figure once and then put her in storage.

What I'm worried about is, if I use Thanos with Infinity Watch would I need someone else to offset the huge advantage Thanos gives any team he's on?

Obviously swarming will be a mitigating factor.

Anybody else I add, should have a mindset that would allow them to be comfortable working with the Magus.

NOva Blast on Magus should be a good way to balance the scales.
A lot of alien generics have the Warrior keyword just like Magus... worth looking into, IMO.

Doesn't it damage friend as well as foe though?
I've always been reluctant to damage allies. Though I could easily see Magus doing it if it would ensure victory.

True dat. The beauty is that Magus does not have to take feedback damage though... Think of it as a last resort.

I'm pretty sure I have it, but I still think I might need more to cope with Thanos. The last time I played Thanos with Infinity Watch he slapped all the SuperSkrulls around like they were beeyotches.

Magus is future version of Adam Warlock, so you could throw him into the mix.

Disbanded is a must-play, as it would eliminate Thanos' Power Cosmic, and it helps to have tie-up pieces to constantly base him.

Adam Warlock and the rest of Infinity Watch will be fighting Magus, that's why I'm worried about Thanos' dominance. I want to see a good fight not a blowout.

Thanos is good, but he's not unstoppable. Especially without any move and attack powers, he'll be almost totally dependent of Moondragon's TK (I am assuming your opponent will use her, since it is an Infinity Watch team).

Now Magus doesn't start with any move and attack powers, either, but if you are playing a swarm of generic aliens, you should have plenty of characters to tie up Thanos and prevent him from really dominating. Just tie-up and chip away while Magus and a couple of others deal with the rest of the Watch.

Really, given how expensive most of the Watch are, you should have a huge advantage in the number of characters you can cram on to your team.

Well actually, I'm my own opponent. I usually just play at home and try to play themed games. Mostly hero vs villain, sometimes villain vs villain, rarely hero vs hero.
I treat the clix figures as a multiverse so I'm not adverse to using DC or Indy figures as long as their participation makes sense.
I could see Blackfire for instance, siding with Magus.

What I won't do, is team heroes with villains they should be fighting against. If there isn't a rational precedent for it I won't team the Joker with Black Bolt just because it makes a strong team for gaming.