Change a character's moral alignment.

[LordUltimus]

Invert one characters morality. Maybe more than one, but not to the "Earth-3" extent. Make Superman always been evil, Lex Luthor always been good, etc., and extrapolate the chain of events and how characters they interact with are affected from there.

[The no face guy]

I would have some sort of angelic entity force Lobo to be a goodie goodie, against his will.

He would be forced to be polite, bring people flowers while sporting a man bun, trade his Harley motorcyle in for a Vespa, and eat only good nourishing plant based food...while deep down inside hating it all.

[TheRay]

Evil Martian Manhunter.
He kills someone and takes over their life, but to commit horrible acts in their name.
The only one who knows he exists is a heroic, mortal saint named Vandal Savage.

[OopsIdiditagain]

Chaotic neutral Joker, he doesn't kill people but he does troll/prank people in potentially unethical ways.

As a result Batman still hates him but has less of an excuse to fight him.

[j9ac9k]

Hal Jordan, you have been selected to be a member of the Qwardian Anti-Lantern Corps...

[Agent Z]

Ares defends and protects the vulnerable from the ravages of war.

Cheshire fights to save victims of human trafficking.

[manwhohaseverything]

Superman lands near gotham city instead of metropolis,Kicks the evil rich overlord dictator batman and his corrupt cyborg commissioner gordon on his pay roll,that too on behalf of the common man.Clark joins the gotham gazette disguised as the mild mannered reporter. Also,he tells joker that his shtick is getting old and harley quinn that she ain't a victim.He fixes gotham.the end.
Note:-Superman was found by motorcyclist.He was raised by along with flying graysons.Clark worked as strongman as kid.His powers don't come from the sun.Dick grayson is his nephew.There is no kents.Clark doesn't know he is an alien.The story is about superman.The gladiator for truth and justice.

[TheRay]

I would have some sort of angelic entity force Lobo to be a goodie goodie, against his will.

That doesn't sound very interesting.

[The no face guy]

That doesn't sound very interesting.

Lol...not for the Lobo we love...but I think it would make for some good comedic relief.

[TheRay]

Well more to you then I guess.

[The no face guy]

We all have our personal tastes...I'd just prefer something light hearted, as oppossed to your idea of an evil martian Manhunter murdering someone....so he can become a body snatcher carrying out horrific acts.

But if you note, I politely didn't call out or critique your idea.

[TheRay]

That is a welcome change of pace on the internet these days, I must say.

[The no face guy]

Well were not all internet trolls on here thankfully....

I prefer to engage in positive dialogue when possible, no one wants a toxic environment.

[TheRay]

Oddly some do.