Decepticon leader

Among the Decepticons, there is one guiding principle: rule of the strong. Where as the leader of the Autobots consults his subordinates, the strongest and the most powerful Decepticon leads, everyone else is expected to follow without question. But strength of body is not enough. One must also have the brains to lead, the intelligence to outwit their rivals and plan their victories. Thus, the Decepticon leader is the strongest and smartest of their ranks.

Guess how many Decepticons think they qualify.

Marvel Comics
Megatron was at first the sole Decepticon leader. Under his leadership, much of Cybertron was conquered. ''When Megatron disappeared, Trannis siezed power, destroying Iacon and forcing the Autobots underground. After the Wreckers killed Trannis, Straxus took command of the Decepticons on Cybertron.''

When Megatron was defeated shortly after the Decepticons reactivated, Military Operations Commander Shockwave defeated the Autobots and usurped Megatron, reducing him to second-in-command. However, Megatron was soon defeated by the Dinobots, allowing Shockwave to fully assume command. Megatron's subsequent return saw a joint leadership, while Megatron was able to use logic to convince Shockwave to give him full leadership. After seemingly killing Optimus Prime, Megatron went mad and apparently killed himself, allowing Shockwave to assume full leadership again.

Meanwhile, after receiving a mayday from the Earth bound Decepticons, Straxus constructed a space bridge that linked Earth and Cybertron, only for Straxus to be killed when it was attacked by Perceptor's resistance cell. Fuel Auditor Ratbat emerged as the most powerful Decepticon in Polyhex, entering into an uneasy alliance with Shockwave. While this was going on, the Decepticon Scorponok took his unit to follow Fortress Maximus to Nebulos, where he underwent binary bonding with Zarak. Following Fortress Maximus to Earth, Scorponok also entered an uneasy alliance with Shockwave and Ratbat. With this many bytes of aggression, the stage was set for a coup.

Ultimately, it came about that Air Commander Starscream was the catalyst that launched a rebellion. When the Decepticons learned that the legendary Underbase was coming to Earth, Starscream caused the Decepticons to turn against each other. By the end of the conflict, Shockwave was presumed to have burned up on reentry into Earth's atmosphere, Ratbat was shot dead by Scorponok, and Starscream killed when he tried to absorb the Underbase's power. Without any rivals, Scorponok easily settled into power as Earth's sole Decepticon leader.

''Meanwhile, on Cybertron, Thunderwing petitioned the Decepticon High Council to be appointed leader of the Decepticon army. His bid was successful.'' Learning that the Autobots were searching for the Creation Matrix, Thunderwing managed to gain the Matrix and corrupted it. Thunderwing was ultimately killed, and the Matrix believed destroyed. With Unicron fast approaching Cybertron, Optimus Prime made the decision to surrender to Scorponok, in return for allying with the Autobots against Unicron. Scorponok planned to betray Prime, but Zarak latter agreed to the alliance. However, Scorponok's troops were growing disgruntled, especially by his recruitment of Starscream, who had decimated them months earlier then was resurrected by Megatron, who had survived his space bridge suicide (only to be fused together with Autobot Chief Medical Officer Ratchet). Taking advantage of this, Shockwave, who had survived his burn-up, managed to get several disgruntled Decepticons to ally with him and attack Scorponok's group. Ultimately, they were all transported to Cybertron by Primus, who named Optimus Prime as the commander of Cybertron's united army.

During the battle with Unicron, Optimus Prime and Scorponok were both killed. As Shockwave and Starscream fled the dying Cybertron, Bludgeon was acclaimed Decepticon leader by the surviving Decepticons. He led the Decepticons in the conquest of Klo, then massacred the Autobots who arrived to stop them. However, Optimus Prime had been revived by the Last Autobot, whom Bludgeon had worshipped as the Ultimate Warrior. The Last Autobot revived the fallen Autobots, and Bludgeon agreed to lead the Decepticons into exile...planning to bide their time.

Shockwave, meanwhile, had hijacked the Ark alongside Starscream with the intention of using it to conquer Earth. He didn't count on an alternate timeline Galvatron to have attempted the same thing. He also didn't count on Ratchet and Megatron to be on board the Ark in stasis, though, nor did he expect the pair to awaken during the journey. While Megatron kept Shockwave and Starscream occupied, Ratchet forced the Ark to crash violently into the ground. Galvatron was the only one to emerge from the crash, and he appeared to be the only survivor.

Generation 2
After his resurrection, Megatron challenged Bludgeon for leadership of the Decepticons. After a fierce battle, Megatron emerged victorious.

Generation 1 cartoon
At first, the Decepticons were lead by an old Decepticon who could not transform. However, when he lost the Second Cybertronian War against the Autobots, he was replaced with Megatron, who lead the Decepticons to conquer much of Cybertron. However, when Megatron and Optimus Prime disappeared, the war on Cybertron entered a stalemate. Shockwave had been appointed Guardian of Cybertron in Megatron's absence, and became de facto Decepticon leader. Once Megatron resumed contact with Cybertron, Shockwave resubmitted to his authority.

Air Commander Starscream, long contemptuous of Megatron's leadership, made several attempts to supplant Megatron. They all ended with failure, usually due to his own impatience or the other Decepticons loyalty to Megatron. However, Starscream eventually decided to get some help. He made plans with Blitzwing and Astrotrain to trap Megatron in a tunnel and freeze him. However, the Triple Changers betrayed Starscream, leaving them both to freeze, and proceeded to wreak havoc. Megatron and Starscream were freed due to an accident on Astrotrain's part, and after defeating Astrotrain, Blitzwing, Devastator, and Starscream, Megatron resumed leadership of the Decepticons.

By 2005, the Decepticons had conquered Cybertron. However, the Autobots retained a control of two moons and held a reserve force at Autobot City. Megatron launched an assault on Autobot City, where he and Optimus Prime motrally wounded each other. During the trip back to Cybertron, Astrotrain required the Decepticons to jettison excess weight or he would be unable to make it back. The wounded Decepticons were thrown over board to allow the survivors to return, with Starscream personally ejecting Megatron. After a mild scuffle aboard Astrotrain, Starscream emerged as the new Decepticon leader. However, Megatron was discovered by Unicron, and reformatted into Galvatron. With a new body and troops, Galvatron returned to Cybertron and killed Starscream with a single blast. Galvatron was hailed as the new leader of the Decepticons.

After Unicron's attack on Cybertron and the disappearance of Galvatron, the Decepticons fled to Chaar. Without strong leaders like Galvatron, Starscream, or Shockwave, the Decepticons fell into a period of disunity, where they fought each other for scraps of Energon. Ultimately, Cyclonus located Galvatron, who reorganized the Decepticons.

Robot Masters
After the disappearance of Megatron, the leadership of the Decepticons was helmed by Starscream. However, a Megatron from another time challenged Starscream for leadership and won.

Dreamwave
At first, Megatron was the sole leader of the Decepticons, with his chief lieutenants being Air Commander Starscream, Military Operations Commander Shockwave, and Communications Officer Soundwave. After Megatron was believed to have been destroyed along with Optimus Prime in a space bridge explosion, Shockwave became Decepticon leader. However, Starscream and High Auditor Ratbat broke off from the Decepticon army, forming the Predacons and Ultracons, respectively. Megatron's return to Cybertron saw him resume command of the fragmented Decepticons.

After Megatron, Starscream, and Soundwave disappeared chasing Optimus Prime's crew aboard the Ark, Shockwave emerged as Decepticon leader, this time as part of a triumvirate that included Scorponok and Ratbat. He was briefly overthrown by Skystalker, who used his head to issue commands to Shockwave's troops, but Skystalker was defeated and Shockwave resumed command. . With the Great Shutdown, all Transformers entered a period of enforced stasis lock. Shockwave was reactivated by Unicron's herald Scrouge, but Shockwave defeated Scourge, studying him. Learning secrets about Cybertron that Megatron had previously discovered, Shockwave made peace with the Autobots, installing himself as Head of State with an Autobot High Council as a legislature. On Earth, Megatron retained command of the Nemesis crew, but he was defeated when Shockwave arrived, intent on gaining the Matrix from Optimus Prime. Starscream ejected Megatron from the ship transporting them back to Cybertron, then recruited the Nemesis crew and the Combaticons to conquer Earth. When Optimus Prime was brought to Cybertron, he united the Autobot resistance groups and overthrew Shockwave.

Meanwhile, Megatron was repaired by Wreck-Gar, and managed to locate a trio of Air Warriors he used to recruit the Predacons. Heading for Cybertron, he took command of Shockwave's forces, forcing Shockwave into a subordinate state. On Earth, Starscream's failures against the Autobots and Sunstorm made Soundwave, his cassettes, and the Seekers all too willing to mutiny against Starscream in favor of Megatron.

Animated
Styled Supreme Leader, the title was held by Megatron for over four million solar cycles, since the days of the Great War. When Megatron was believed killed trying to secure the All Spark, Starscream immediately nominated himself the new Supreme leader...no one took him seriously.

Trivia

 * Unlike the Autobots, whose leader is called a Prime, the Decepticon leader has not official name or rank.
 * Being Decepticon leader means that Laserbeak has to perch on your shoulder. Seriously.