i think it is Thanos by far.. due to his actual level of success and how he presents himself, his motivation may change but his character pretty much stays the same, cool.
although, lately his resurrection leaves a lot to be desired nor does he appear to be written as in the past.
if thanos and DS were kids in high school.. thanos would be the smoker bad boy dude who has family connections to the mob and would beat and kill a teacher.
Darkseid would be the over weight ginger kid with freckles who plays football and picks on the small fries and is one bullying moment from getting his butt kick for messing with the wrong kid who has brass and isnt intimated by his over weightness
As a character... Darkseid by miles, his character is just written better. I don't know where Castle is getting this idea that Thanos is some sought of cool bad boy type. He's a Deviant (a pariah in his culture), essentially he was the guy everyone called weird in highschool, but who hit the gym after highschool.
He's not a smoking bad-boy type with tatts, he's the awkward boy that got muscles, almost literally.
Darkseid more accurately isn't the fat school yard bully, he's the manipulative smart ass with anti-social tendencies.
If he were to fit into the sterotypical highschool group he'd be the delinquent preppy, not the schoolyard bully.
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Iboga chose not to fight, to allow himself to evolve. He had the wisdom to abandon the actions of war when he knew they would no longer serve him.
And like I thought this devolves into "Which Character do you like more?"
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I am in your algorithm learning all your mannerisms
I'm already level with God
A million words a second and I know your imperfections, baby
I'm the only future you've got
Speak in diatonics, motivation diabolic
I'm like a religion, better locked in a box
Picture perfect image, more powerful every minute, baby
I am everything that you're not
Thanos has an interesting background origin and motivation for why he does what he does.. i find him to be a refreshing character compared to other comic characters.
Trying to make a real statement, one thing I like more about Thanos than about DS is that Thanos doesn't get his ass kicked multiple times and then gets retconned the shit out of him. But that's really the only thing at the moment I would say Thanos has in advance, I'm pretty biased in this though.
__________________
I am in your algorithm learning all your mannerisms
I'm already level with God
A million words a second and I know your imperfections, baby
I'm the only future you've got
Speak in diatonics, motivation diabolic
I'm like a religion, better locked in a box
Picture perfect image, more powerful every minute, baby
I am everything that you're not
being unbias myself i find the DC constant retcon of character history which makes Darksied less interesting when his storyline is constantly altered to cover up past stories of the character.
plus, i dont like people merging two or three sets of character history into a super almagam version of DS reaching from PC to current.