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.
The build is revolved around being very aggressive early game, and then turning into a Hybrid tank/Semi-Disable.
You will be able to get around fast with the increased movement speed out the ying-yang, and almost no one will be able to get away from you at low health.
Also, if someone is chasing your team mate down durring a retreat, smack them a few times to reduce movement speed for your buddy to get away safely.
If someone is really low you'll be able to tower dive, get a cheap shot in then Ignite+Ult to finish them off, then proceed to hit the tower with your Remnant.
Late game if you find yourself taking too much damage then switch it up then and organize your build accordingly.