Agreed, I managed to get RottingMage but cant seem to get the other 2 and all I do is run the dungeons over and over again until my energy is gone.

Doing the dailies and just enough challenges to get more energy and do it over again.

I come to search the forums to find out if it is just bad luck and with a google search I find an old post from July 2019 not wanting to necro I search the front page and after the spam posts from scam sites, I find your post.

They will always answer like this:

"It's all RNG"

Heck, one of my champion has 96% crit rate, and the crit doesnt proc quite often.

WIth logic like this, the champion drop rate in dungeons probably around 0.005%.

Anyway, I bet we gonna hear "it's all RNG"  again either from mods or undercover plarium staff who pretend to be normal player just to say

"it's all RNG, I got the champ from less than 100 energy"