Hello my name is Jan Solo Queue and recently i've reached diamond 5 as a Jungle and Support main, and this is my guide to my current favorite assassin Fizz.

For runes i like to take the regular jungle runes that i take with most of my tanks, the attack speed and cool downs should give you fast enough clears in the early levels.

With the new black cleaver introduced in patch 5.8 i think fizz is one of the junglers that benefits most from it, the reason being that the phage passive lets you stick to your enemies easily, and the 20% cdr is perfect enough to have various rotations of spells. I like to buy the frozen gauntlet as my third or fourth item in order to have 40% cdr together with runes and masteries, plus it gives you the ability to stick with the carries and not be kited around. I personally prefer the skirmishers saber as the best smite upgrade and cinderhulk gives you enough survival in the jungle in the early levels and the ability to gank early with enough tankiness to possibly tower dive.

With the state of the current meta, i think high dps assassins are still high priority specially someone like fizz since his w active shreds trough most tanks and he has an easy time getting to the backline due to the nature of his abilities.