Are you very sure you understand what Stratis is all about, it is only in Dash and its clones that you can find Masternodes. Stratis is a proof of stake coin, you can only stake your coin using their wallet
At the moment there are no masternodes.
It has been mentioned on Slack that in the future Stratis maybe will have some kind of masternodes as well. No specifics have been released. These masternodes or how they will be called would have to do something with tumblebit probably.
I think with or without masternodes Stratis has a good chance to follow the footsteps of dash or ethereum eventually in terms of accomplishment.