Honestly - void brews are by far the worst of the set, but I still wouldn't use them, at least not yet. Warcaster won't really help you much right now. Just stick him in your vault for the time being.
Ok. So all these rares/epics in the vault... I shouldnt level them but I also shouldnt use them as food... what are they used for?
Ok. So all these rares/epics in the vault... I shouldnt level them but I also shouldnt use them as food... what are they used for?
Honestly? Who knows. It's too early right now for you to be making those decisions. Some of them may end up being useful later. Others will eventually be turned into food. But you won't know that until the rest of your roster starts getting fleshed out.
The problem with leveling any of those now is that there's a pretty good chance you'll get better replacements before they ever become useful. Or, in the case of a champ like Warcaster, they may never end up being useful, because you just don't end up getting the other champs you need to make him useful.
The number one rule of this game is patience. The more patient you are, the faster you'll be able to progress. It's deceptive, but it's true - if you're impatient you end up burning resources at the wrong time, and then end up being stuck for a much longer time when you need them.