Is he really superior to Ego though? He's his creator, but Ego is definitely the most powerful here. Though he's vulnerable as all shit. Stranger is Pluto level when Pluto's in his own realm.
And not to mention while he was with the Cosmic Deities battling Thanos with the IG, the Skyfathers were stuck in Asgard and helpless to join in or do anything.
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..even the outer hells are indifferent matters for they bow only to potent and archaic Nodens.
Stranger's best feat was probably directing the energies of the Infinity Union back on himself (not absorbing) and only getting badly injured in the process.
When Nebula had the powers she was casually erasing and recreating the universe. Mind you she also casually erased and recreated Stranger too, so...
He's definitely high up there, but I personally wouldn't put his power above Ego's. Though he might win in a fight. Thor is the most well rounded IMO.
^ That's a pretty ambiguous feat, imo. As you said so yourself: Nebula was able to destroy and re-create the Stranger just fine not to mention that it was stated that the energies of the infinity union are too powerful for the Stranger; yet, when he somehow re-directs the energies of the Infinity Union unto himself, he was able to tank it fully?
Creating Ego and Alter Ego is his best feat, imo.
He has quite a lot, actually.
Getting knocked around by a Juggernaut punch (iirc, Hulk also knocked him around more than once, in their 2nd encounter, not first). A weakened Silver Surfer caused him trouble in their first encounter, Thor was able to use time manipulation to prevent a battle between the Stranger and Asgard, making him actually forget; Champions were able to fight the Stranger and tank hits from him. hell at one point, Spiderman was giving Stranger trouble. Along other instances which im sure im missing. The fact that he wanted to destroy Earth more than once, yet resorted to some scientific means or using someone like the hulk to do it, is also not a very good showing on his part.
He's also looked like a fool at times; like when he kidnapped Magneto into a planet of his, he left him with a ship which perfectly fits with Magneto's capabilities to be able operate it.
He has faught the Watchers before. How many who knows. Believe the Pluto incident he knew the outcome. Juggernaut reference isn't that non canon. IMHO, Stranger> Uatu> Ego> KT. May change if Thor defeats G