Episode Pro is a transcoding application made my Telestream. If you have an axle Gear, Episode Pro was included with your purchase to generate the proxies for axle. You can also use Episode Pro without a Gear, if you choose.
The primary advantage of using Episode Pro is that it can push the transcoding work off the axle server and onto a seperate computer, leaving axle with more processing power.
Episode Pro has its own documentation, you can find it here.