Okay guys, I gotta say, I really like the idea of the reserves, but I just have a problem and I just want to know if this annoys anyone else. So there is an offense and a defense reserves formation on two different tabs, but what annoys me is that I want to use a hero I have as my main offense as a reserve for defense but some reason I can't!  Why have two different reserve tabs if I can't use a main offense hero as a defense reserve?? Look, this is why: 
My desired offense:  Wolf, TS, WT, Chiron, and abyss with RV as a reserve
My desired Defense: Wolf, WT, Ironclad, RV, and abyss with TS as a reserve simply because I like renee's fortitude skill better than Toxic's. 

But these are not possible together currently and I would really love it if a future update will make this possible!

IGG support told me fortitudes are active when hero is in bastion.