Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Threats to Rumble with this build
In lane rumble doesn't really have combos, but once you get to the mid game your ultimate can swing team fights either way, so having a good ultimate is very important. With your ULT you want you either zone, trap, or just land it on as many people as possible. If the enemy bunch up using you ULT to engage for you team is a great idea. If the fight has already started you need to look to either trap enemies against something like a wall in lane or in the jungle/river zone them by blocking passageways. Zoning enemies in the jungle is very useful because if the enemies your tried to zone walk through your ultimate they will take lots of damage and be easy to take out.