Hi there community my name is Klymstra and this is my guide of how to pass the "HARD" stages to get to the next heros.
1. From Takeda the Blade Assassin to Eistor the Banisher their is no really trick to pass that phase you juste need to go as far as you can and prestige.
2. From Eistor the Banisher to Flavius and Oinksbjorn once you reach jj money you can evolve Twitterella the Tweeter and after evolve Master Hawk, Lord of Luft, and you should reach Eistor, but you may not need it cause you have enought dammage and they dont bring a big bonus.
3. From Flavius and Oinksbjorn to Chester the Beast Tamer whm you have oo you evolve Teeny Tom, Keeper of the Castle, and you should have Chester around lvl 540 easily.
4. From Chester the Beast Tamer to Mohacas the Wind Warrior once you can evolve From Flavius and Oinksbjorn that cost something like 3.3 vv (if you have the price reduction -50%) you need to evolve him.
5. For the further stage and "hard" phase you all ways make evolve the one that was just before the last one
example to reach Dark Lord, Punisher of All, you have to make evolve Pixie the Rebel Fairy whem you can so she gives you a big boost dammage.
6. For the last hard phase witch is actually really hard ^^ is the one to make evolve Dark Lord, Punisher of All, you have to be patience and prestige some times until you reach something like 110'000% bonus dammage (you can reach it with less but is really long and you may take more than 45 sec to kill a monster) the cost to make him evolve is 5.6 E^188 if im not wrong. and you should reach that around lvl 2385 or near it. For him is it useless to evolve Jackalope the Fireballer since he has only 40% and 20% bonus dammage early bonus whem evolve, and it makes you loose 30% more dps (his bonus at lvl 400)
Remmember is it useless to evolve the early heroes, beacause they dont give enought dammage to make the difference and you will have to make them lvl up again to have their bonus.
If you have any question fell free to add a comment or ad me as a friend and ask in game :)
Friend code: rg3rjy
Hope you guys like it and found that help full. Cya :)