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SPOILERS!!!!!



Having arrived to the Sokovian church, dressed in his new Mark 45
Iron Man armor, Stark was confronted by Ultron in his new vibranium
form. Ultron deduced that Stark was stalling to protect the people of
Sokovia in which the latter affirmed Sokovia was meant to be Ultron's
target for his main plan. Ultron countered by saying that he has moved
beyond his mission and that he is free.



Ultron Sentries
emerged from the ground and began to terrorize the citizens of Sokovia,
prompting Iron Man and the Avengers to defend them. Ultron was then
confronted by the Vision, whom Ultron recognized as the synthetic body
he had planned to use as his initial final form. Although Vision tried
to reason with Ultron, the latter grabbed and choked the former in the
air, allowing Vision to access Ultron's mind and effectively cut off his
connection to the Internet. Tired from the skirmish, Vision was
incapacitated by Ultron who remarked how the Avengers have taken
everything away from him. Ultron then activated the vibranium detonator
inside the church thus enacting the first stage of his main plan. Dust
erupted from the outskirts of Sokovia and the city began to rise into
the air; revealing that Ultron's machine underneath the city's landmass
allowed it to forcibly lift the entire city into the sky with the
Chitauri's anti-gravitational technology found at Strucker's base.



When Sokovia further rose into the sky, nearly approaching the
Earth's atmosphere, Ultron gave a speech as his Sentries began to
terrorize the Avengers and the citizens of Sokovia. Ultron then attacked
Thor in the air, having recognized him as a noteworthy obstacle. The
two engaged in battle after Ultron threw him down into the church.
Though Ultron was able to outmatch Thor, the latter hinted at stalling
the fight, after which Vision emerged and hit Ultron away using Mjolnir.
Though it seemed as if there were no means of evacuating the citizens,
the Helicarrier arrived to the rescue with War Machine, Nick Fury, Maria Hill and Cameron Klein. The Ultron Sentries attempted to sabotage the Helicarier, only to be destroyed by War Machine.

"Age Of Ultron"

"This is exactly what I wanted. All of you, against all of ME!"
―Ultron^[src]




Ultron commands his army



The Avengers deduced Ultron's final scheme: he plans to raise the
entire city of Sokovia into the sky and crash it back down to Earth via
the machine located underneath Sokovia's land mass; as means of
replicating a meteor and creating an extinction-level event dubbed as
the "Age Of Ultron". The entire Avengers gathered inside the church to
defend the vibranium detonator and prevent the city from crashing, with
Thor decidedly taunting Ultron. Ultron summoned the entirety of his
Ultron Sentries for one final battle and relished in the notion of the
Avengers failing humanity while making way for the new age. Ultron
commanded his entire army to attack the Avengers all at once from all
sides of the church. Through the combined efforts of the Avengers, the
large number of Ultron Sentries were slowly reduced until there were
barely any left.



Ultron finally joined the battle and fought against Vision in an
aerial confrontation, with the two hovering and circling above the
center of the church. Though Ultron seemingly outmatched him in physical
strength, the Vision blasted Ultron with the power of the Mind Stone,
essentially pushing Ultron outside the church. Iron Man and Thor joined
in and fired at full blast towards Ultron; using their repulsors and
lightning respectively. With Ultron kept at bay through the combined
efforts of Vision, Iron Man, and Thor, Ultron's vibranium armor began to
melt and peel away. The three would halt their combined assault, only
to find Ultron still standing, albeit greatly damaged. Before Ultron
could finish remarking toward them, the Hulk dashed in and punched
Ultron into the air.



Most of the remaining Ultron Sentries attempt to escape as means
of allowing Ultron to retain a substitute host body, though most of them
were chased down and destroyed by Vision and War Machine. With his
vibranium armor effectively damaged, Ultron decided to hijack the
Avengers' vacant Quinjet
and fired its ammunition at civilians. Hawkeye, upon realizing that a
kid was in danger comes to the rescue and Ultron attempts to shoot them
both. However, Pietro Maximoff arrives in a flash, only to sacrifice
himself to Ultron for Hawkeye, much to Wanda's misery. The Hulk jumped
inside the Quinjet's open hangar and threw Ultron back out, in which the
latter crashed near the church.



Injured and weak, Ultron was confronted by an angered Wanda who
had abandoned her post from the church. Though Ultron still showed
sympathy and concern for her safety, Wanda related her painful
experience of losing her brother and likened it to dying. Wanda pried
out Ultron's robotic heart and crushed it, inadvertently allowing him to
activate the machine inside the church through one of his Ultron
Sentries. Although everyone was evacuated, Sokovia began to plummet.
Thor and Iron Man effectively destroyed the entirety of Ultron's machine
and the landmass containing Sokovia's capital city, thus stopping the
"Age Of Ultron" from coming to fruition.


Source:http://marvelcinematicuniverse.wikia.com/wiki/Ultron