Killer Instinct's new story mode Shadow Lords won't be released until September 20th, but Iron Galaxy is giving a select few a chance to check it out early.
If you are interested in beta testing the mode, then you can sign up to possibly get into the early access program here http://www.ultra-combo.com/signup/
Here is some important information to keep in mind about the trial program
Iron Galaxy says that there isn't a number of open beta slots available but they are adding players based on what they need to test out the mode, so entry into the early access program isn't promised or guaranteed. Even if you don't get in, the mode is supposed to launch in a few short weeks anyways.
Not sure what Shadow Lords is? Check out 16 minutes of gameplay of the mode courtesy of IGN from Gamescom 2016