Upgrade champions

Kriptonit3

I have 4* Vision, Guillotine, Cyclops, Storm, Spider-Man (miles morales) and Captain America all on lvl 3/5 and all ready to upgrade, I only have enough at the moment to upgrade 1 champion. Which one should I upgrade for attack purpose? Thanks

Isman1998

For attack I would take up either guillotine or vision. Vision power controls and guillotine can hit really hard. Her bleed is great too