Would like to see teams, champs, etc. but at that stage of the game it could be as simple as their champs just have better gear than yours.

I understand they have better gear, that's what I'm asking. What gear could he be using to take so little damage. There were only two of them and one of his was just like mine. Same guy, level and we both had five purple stars. But my four guys did no damage to either of his.

Sounds like it may have been Stoneskin.  Which is a set you earn from Hydra Clan Boss chests and mitigates most damage.  Like Thorne said we would just be guessing without screenshots though.