Most Difficult MOBA characters (Heroes/Champs/Gods, etc.)

Lately I have noticed League of Legends is releasing much more diverse and difficult characters with Ekko, Gnar, and more. This is board was created to discuss and see how the versatility and difficulty of these recently added champs as well as some older ones which have a high learning curve compare to the "most difficult" characters of other MOBA's. Possibly even discussing what insightful ideas we can modify from these deemed difficult heroes of competing MOBA's and input them nicely within our game of LoL.

Thx for responses in advance

...and I think I'll start off the list with this suggestion

Most difficult: Monkey King from HoN I think he takes the mobility of the monkey specimen to a whole new level Wukong and sun Wukong from smite could never reach. I think we should have more characters that interact with environment the way Monkey King did which makes the learning curve not only to master how you utilize the champ but also the map!