If they tried direct assault they'd lose. If the did something clandestine like slowly infecting the populace of DC Earth with a modified TO virus that, when activated after maximum pandemic levels, would turn the millions of Earth's human inhabitants into beings like The Harbinger of Apocalypse, they would have a chance.
If Apoc and Ultron work their tech to be like the Phalanx infection and attack precise target they would be much more of a threat together. I'd like to see what Ultron is capable of after the Ultron wars.
Yeah, I was thinking of a Phalanx-type infection as well. They should go after Batman first (turning him into a select) and have HIM infect the rest of the JLA slowly....
It'll be a loooong campaign, but not a single shot needs to be fired before the entire DC Earth gets conquered.
Ultron and Apocalypse are among the best organic/biological experts in the Marvel universe, they could probably make a biological virus coupled with the Phalanx virus or just make the infection so it would evolve to be indetectable Victor Mancha style. Both characters have quite in common actually.
I'm thinking they contaminate the food and water supplies of less prominent nations to build up an army of operatives via infection, then use those operatives as pawns to infect people in countries where DC Earth's metas are more active. By staying in the shadows until they get their numbers into the millions, Apoc and Ultron ill have a distinct advantage. They could probably subvert the Rocket Red Brigade as well.
they infect batman only for six months later, when they're on the cusp of victory, to have him reveal that he let himself get infected, and makes a counter-infection that destroys them.
__________________ "You must begin by gaining power over yourself; then another; then a group, an order, a world, a species, a group of species... finally, the galaxy itself."
- Darth Plagueis
"She may be small but she packs a punch and when shes in this mood...she goes for my danglers" - Oghren, Dragon Age
Lol. There's really no need to go after any heroes directly until after the general populace has been significantly compromised. If 80% of Gotham has been infected, infecting Batman directly isn't really a priority.
I guess anything is possible. Given the multiple times DC Earth has thwarted would be conquerers, world destruction and the end of all things, I'll go with the odds and say team Ultron/Apocalypse don't get it done.
Another thing to take into account is that Ultron could probably detonate every nuke already on DC Earth simultaneously while they are still in their bunkers or launched. He and Apocalypse would have no problems with the fallout.
The OP says take over or kill all of DC Earth. If they use the TO/Phalanx/Harbinger plan synchronized with detonating all of the nukes on DC Earth (i.e., activate the infection, turn all of the infected into techno-organic Harbingers, then set off the nukes), if the planet isn't destroyed outright, the casualties and collateral damage would be huge. Most heroes with human level durability would be dead instantly, the ones that didn't would be dying of severe radiation poisoning, and the resulting nuclear winter would render DC Earth's top gun Supes in a tough spot as the Sun would be completely blocked out. The Survivors of this nuclear holocaust would then be pitted against millions of TO infected Phalanx/Harbinger killing machines in an extremely hostile environment.
Playing it smart, Ultron and Apocalypse can at least tip the scales heavily in their favor.