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.
If you dont level up creeping death your Q and E will do massive damage early game. Morde is a great pusher and nothing can stop him early game. If you wait to long to finish the game you will be crushed. Morde is a great mid and if you can solo mid you can farm alot more and then this build will be alot more effective. once you get your enemy to about 20 health flash in and ignite and use your ultimate so it stacks.