When Starscream threw
Megatron out of Astrotrain, he floated towards Unicron. Unicron
rebuilt Megatron into Galvatron, a more treacherous Decepticon
leader. Galvatron's first order of business was to get revenge on
Starscream. After Starscream's destruction, Galvatron led a campaign
against the remaining autobots to acquire the Matrix of Leadership.
When he acquired it, he tried to make his master Unicron, into his
slave. Unicron swallowed Galvatron and commenced an attack on
Cybertron, After a fight with Hot Rod (who then turned into Rodimus
Prime), he was defeated and thrown through Unicron to land on
another planet. After the Autobots regained Cybertron, the
Decepticons lacked a strong leader and they lacked energy. Cyclonus
(Galvatron's second in command) led a search party to find
Galvatron. They found him, but he was damaged mentally.
He was driven by hate and would not think out his actions. His first
act after being revived was destroying an EDC comand post. From then
on, Galvatron led the Decepticons, but not that well. He also
ordered the Constructicons to build Trypticon (the Decepticon City
which was able to transform from a T-Rex to a city) and it's home
was on the planet of Charr (that's where the Decepticons all
regrouped after Rodimus Prime annexed them from Cybertron). When
Rodimus Prime threw Galvatron out of Unicron, he landed on a planet
and became mentally deranged.
Later, he was fixed on a planet which was alive by a race called The
Torkulons. The Quintessons actually tricked Cyclonus into taking
Galvatron there was a very good chance galvatron would not survive.
Galvatron repeatedly tried to escape and tried to kill the Torkulons
and he actually did. But not until their living computer absorbed
his insanity. Towards the end of Even though Starscream was
destroyed, he did come back to try to take his revenge on Galvatron.
His ghost came back and inhabited the body of Scourge. In that body,
he did considerable damage to Galvatron until Unicron rebuilt him
and Galvatron destroyed Starscream again.
Towards the end of Galvatron's reign, he ordered many Decepticon
attacks on Japan (that's not fair, I mean, Japan isn't allowed to
have any sizeable military, and they suffer from volcanoes,
earthquakes, and giant frikin lizard attacks. its just not fair). In
that time, two of the Stunticons drag raced Rodimus Prime and they
acquired the Matrix. Galvatron tried to use it as a weapon, but the
spirits of the Matrix (including Optimus Prime) came out and scared
the bejeezus out of him. He ordered it to be destroyed, but Scourge
took it to power himself up. Scourge defeated Galvatron, but when
Scourge lost the matrix, Galvatron severely punished Scourge.