If you backed the Kickstarter, yes it is coming with OblivAeon as one of the stretch goal rewards. If not then no, you will have to buy them separate from that expansion.
We don't know how they will be sold after the kickstarter pays out, whether it will be a mega-mini-expansion with all 4 characters or just individual mini-expansions with a single deck (like Unity or The Scholar).
EDIT: To make clear, these are 4 new decks (1 character card and a 40 hero card deck each), one for each of the Characters in The Sentinels team hero from Vengeance.
Yes, I backed the Kickstarter. After I posted, I saw that I have them as Foil Character Cards. They just weren't in my spreadsheet and the page description didn't make clear what these were from. The other KS exclusives (to my knowledge) are all noted as such.