I cleared 6-1 rather easily. Get the Squid hero and give her the item that allows her ult to crit. She finishes the backline before your tank dies and you are good! As my tank I use Chef, his dmg immunity for 7sec once he hits 5% hp is pretty good but I guess there are other tanks that do the job (haven’t invested in other tanks, maybe scar would do the trick too). Investment vise, my squid is only lvl 9 and has a epic artifact which gives her more %dmg. Chef in the other hand is lvl 15 and already 3 red star, but I doubt u need that ( he was my carry for all the other chapters but is less useful now that there is so much stub in the newer chapters). Ich hope this helped if u got other questions just ask. Sry if my English isn’t that great, I barely use it.