Yes. Every IO-Link Master also counts as a device when setting Neuron up on your installation because, besides being one of the links between your IO-Link devices and Neuron Edge, it has information to show on Neuron App such as operating voltage, the number of connected sensors, connection status, etc.
So, when you customize Neuron's configuration on your installation, you'll have to add the number of IO-Link Masters you're going to connect.
Our recommendation is that you do so, you establish an Every Minute data upload frequency on the cloud so you can check the data on Neuron App.