Destruction Lineup & Capturing Cities in Last Fortress Underground

Update! Thank you to Punisher776 from Zone 124 for pointing out two things I missed :-) 1) Although you do not have to increase the numerical level of the heroes to access their destruction skills, you still have to ASCEND the heroes to access those skills. 2) There is a third way to get a temporary destructive might boost that does not cost money! You can use Alliance merits.