Hello, welcome to my untypical Jarvan IV guide. Im maining Jarvan 4 seasons from now, and every season when new items appeared and old jungle item got removed I have to change my build a bit. From season 13, I definetely stay on this one, because for me its the strongest for carrying games. My current rank is Master and here is my Jarvan IV stats:
I will be short for guide words. First of all reason for rushing Serrated Dirk is when you got electrocute and dirk in early game you are literally strong enough to burst anyone 75% HP with full combo(And max E+Q range) which is easist possible way to gank, 1vs1 and do early drake. Every time Im doing drake immediately after he spawns (30secs after max)and after Im also playing only for midlane and botlane. Ganking top wont give you anything since you can feed your Irelia or Fiora who can 1vs9 afterwards. Try to perma camp bot, because thats how you will win easiest way possible. Most important thing: PLAY FOR DRAKES. Good luck.

https://www.youtube.com/watch?v=NXR8nXhNNjc This guide look like this