JLU season two is easily the best. It is the perfect culmination of everything that came before, and Waller and CADMUS are easily the most threatening villains of the whole run (except for Darkseid, obviously). Season three is a great ending, too, but season two is a masterpiece.

Here I am looking for the all of the above option because the whole series is a masterpiece of DC storytelling. If I must choose one then I’m going with JLU season two for the reasons stated above. I love how it builds up to whether or not Cadmus is right about Superman and the Justice League going rogue and becoming killers. I love how even the heroes themselves were divided on whether or not Cadmus was right to be afraid of them.

I agree with everything stated above. I’d also like to add that it’s my opinion that all 4(or 5, however you wanna look at it) seasons of JL and JLU together make up the best piece of DC Animated media of all time.

It's a tie between the cadmus arc and jl season 2