Pre-Zero/LoSH Hour Mordru should win comfortably. He's done things that are simply beyond 20th/21st C. Mordru. In his early Adv. Comics appearances he was said to possess power enough to vaporize galaxies, and this power level was kind of confirmed in a bio in an issue of LSH. On top of that, he was always regarded as being a peer to Pre-Zero Hour Time Trapper, same TT who created universes and manipulated all timelines on two occasions (once in Superman #295 and another time in LOSH v4 #4, well the latter chronologically should have happened all the way back to his adventure comics appearances in the 60s) and was stated to be beyond the multiverse in a letter's page of an Action Comics issue, among other things. Also in the 4th Legion title Mordru was said to be fated to rule the universe. While he isn't without low showings, it doesn't change the fact that he's simply above 20th/21st century Mordru.
JSA Mordru's best feat was owning Thunderbolt from inside his own 'lamp'--and remember, T-bolt's counterpart/equal, Lkz, was able to defeat/imprison Spectre. So yeah...
Anyway, pre-ZH Mordru should still win for reasons operator mentioned.
Yeah, that's a pretty solid feat, especially when the Spectre imprisonment happened in an earlier story. But anyway that's also the same Mordru who had help to eclipse the moon. And let's not forget that Pre-ZH Mordru covered an entire sector of space (multiple planets iirc) with darkness.
Also, Thunderbolts kind of useless unless someone tells him what to do. Odds are he didn't even try and defend himself against Mordru in his pen.
__________________ What CDTM believes;
Never let anyone else define you. Don't be a jerk just to be a jerk, but if you are expressing your true inner feelings and beliefs, or at least trying to express that inner child, and everyone gets pissed off about it, never NEVER apologize for it. Let them think what they want, let them define you in their narrow little minds while they suppress every last piece of them just to keep a friend that never liked them for themselves in the first place.
I'll check again, but I could have sworn Jakeem told him to banish Mordru, or something. He takes his commands very literally.
And in the story where Mordru owns Nabu (I think), the Thunderbolt took care of him pretty easily.
__________________ What CDTM believes;
Never let anyone else define you. Don't be a jerk just to be a jerk, but if you are expressing your true inner feelings and beliefs, or at least trying to express that inner child, and everyone gets pissed off about it, never NEVER apologize for it. Let them think what they want, let them define you in their narrow little minds while they suppress every last piece of them just to keep a friend that never liked them for themselves in the first place.