How to get Cleaver in Hero Wars

There are three ways to get Cleaver in Hero Wars. The first is to win him from a Hero Wars livestream (very slim chance), the second is to win him in winterfest and the third way is to pull him from a heroic chest.
I opened chests during the Holiday Hustle event (aka the yearly anniversary event) in (March) 2022 to get a 60% discount on the cost of opening heroic chests.
Normal price for 10 heroic chests is 1500 emeralds and during this event it was 800 emeralds. The same discount is also available during the yearly Cyber-Con (every year in November in the same week as Black Friday).
Watch the video to find out how many heroic chests I had to open to pull Cleaver.
The chance to pull Cleaver from a heroi chest is 0.01% but the chance increases with each heroic chest that's been opened.
I had read that on average it takes 500-600 heroic chests to pull Cleaver. My results are slightly different, but it entirely possible that the developers only increase the chance to pull Cleaver depending on how many emeralds were spend (similar to titan totems) in which case the discount affected my chance.