Originally posted by beatboks
Your facts are a little skewed here.When DS first awakend from his centuries long sleep he he wanted power to bring darkenss to the universe (issue 288 IIRC). There was no mention of him being weakened, nor were there signs of it. he sent his servants ( that he created upon awakening, showing no leesser power than any other pre COIE showings ) out to obtain artifacts of power for him which they did.
We know of two Excalibre and the Orb of Orthanax for certain because we saw them both taken and DS absorb the energy of both. When the Legion went to protect the Orb it was because Brainy had predicted it based on the several thefts of other Tallok VIII artifacts so we also know there were more. After absorbing the Ord DS stated ( issue 288 again if memory serves) that he had absorbed as much energy as he could without drawing it from something living.
He then with one of his servants went to where Mordru was imprisoned. The servant using the power of the astro force ( IIRC DS referred to one as a mockery of his son) the servant freed Mordru. You see DS was actually at a powered peak at this point not weakened. Mordru having just been freed from incarceration was weakened. DS was prepped Mordru was intent on destroying the one who freed him with his back on DS ( he was going to do so quickly as thanks for his freedom). DS then absorbed Mordru's power.
I'm sure if needed I can lay my hands on the issue within a few days to provide scans to prove.
As to the battle.
I'm not up on King Thor (read a lot of classic Thor but very little over recent decades). As I understand it King Thor is at least Odin Level if not above. Mordru wouldn't be Odin level ( not even 30th Century Mordru), though he could fight Odin only because he has a history of draining power from everything ( Souls of Gem world wizards, Lords of Order and Chaos, Starheart, Dr Fate, Speed Force, Rock of Eternity while battling it's master, and many more). As a Battle progressed between Mordru and Odin Mordru would grow stronger from Odin's own energ. Without Prep and power ups DS is not greater than Mordru so he won't beat someone above Odin level.
👆 Nice list of feats.