Metal Overlord

Metal Overlord (メタルオーバーロード) is the second phase of the final boss of Sonic Heroes. It is the finished transformation of Metal Madness which Metal Sonic attained in order to annihilate his arch-rival Sonic the Hedgehog and conquer the world. However, the metallic tyrant was defeated by Team Super Sonic and stripped of his power. The song "What I'm Made of..." is played during the battle with him.

Appearance
Metal Overlord's physical appearance is nearly identical to that of Metal Madness, meaning he resembles a large, blue, heavily-armed mechanical dragon, with two eyes lined up vertically on his head. He has several long spikes on his upper body and many smaller ones running down his back and his long, curved tail. He has a flamethrower as his right hand (though he is not seen using it), and his left hand has four fingers with claws that can be launched, but he has no legs. The only physical difference between Metal Overlord and Metal Madness is that he has grown a pair of mechanical wings on his lower body and detaches himself from the fleet, leaving several cables hanging from the bottom of his body.

History
When deciding to take the matter of defeating his rival Sonic and conquering the world into his own hands, Metal Sonic had the idea of becoming Metal Overlord, a form with the power necessary for both tasks. To achieve this form, Metal Sonic needed data from efficiently strong people, and as such lured Team Sonic to the Egg Fleet to destroy Sonic for good while he would copy the team's data along the way. Additionally, he needed Chaos' data and as such kidnapped Froggy and Chocola. When Team Dark, Team Rose and Team Chaotix joined the adventure, Metal Sonic copied their data as well for Metal Overlord.

After getting the data he need, Neo Metal Sonic transformed into the early stage of Metal Overlord, Metal Madness, by using debris from the Final Fortress. Despite interference from Team Rose, Team Dark and Team Chaotix, Metal Madness completed his transformation and finally became Metal Overlord. Metal Overlord then flew into the skies, intending to make his ambitions come true, but was pursued by Team Super Sonic. Confident however that even Super Sonic was no match for him, Metal Overlord fought the team without hesitation. During the battle, Metal Overlord ranted about his intention to rule over a robotic kingdom and his belief that the real Sonic was his copy. Eventually, Metal Overlord was defeated, and he fell down from the sky in agony, unable to understand how he could lose, before landing on the Final Fortress and reverting back into Metal Sonic.

Powers and abilities
Being Metal Sonic's strongest known transformation, Metal Overlord is one of the most powerful robots Sonic and his friends have ever faced, and probably one of the most powerful beings depicted in the entire Sonic the Hedgehog series. In this form, Metal Overlord is strong enough to fight on par with Super Sonic, Super Knuckles, and Super Tails and even then, the trio only had a slim chance of defeating him, if not even less.

Due to him having grown wings, Metal Overlord is capable of flight and can fly at incredible speeds,  but is still slower than Super Sonic. He is also capable of enormous feats of strength, as he can easily pick up ships from the Egg Fleet with just one hand and throw them. Additionally, Metal Overlord has proven himself to be highly physically durable in this form, nearing that of invincibility. Normal attacks from even super transformed characters cannot hurt him, and he does not appear to have any weak points in this form. The only known attack strong enough to inflict damage on him, is Team Super Sonic's Team Blast, Super Sonic Power.

Metal Overlord can fire rapid barrages of crystal pillars and launch the spikes on his back as homing missiles, much like in his previous form. This time around, however, he can fire them at a much faster rate. He can also fire his left claws as missiles that can trap his target in a crystal cage which is strong enough to hold even Super State user.

Metal Overlord can also perform Chaos Control, possibly due to him copying Shadow the Hedgehog’s and Sonic the Hedgehog's data, which allows him to freeze time temporarily. It is unknown if he can do it longer than that, or if he has the skills to further manipulate time and space.

Boss guide
Metal Overlord is fought in the Last Story as the final boss of Sonic Heroes. He attacks by shooting out crystal pillars, which Super Sonic can destroy with Homing Attack, Rocket Accel, Tornado Spin, or Light Attack (the Light Attack will consume five rings when used, and as such, is not recommended), shoot out missiles that can trap your teammates, which Tails can Thunder Shoot for Team Blast charge, and by throwing large crafts at the player, which can be destroyed by Knuckles (done by using his Fire Combination to create fireballs and directing them at the craft), also gaining Blast charge, though the player can simply move around the craft. Should the player lollygag, he will use Chaos Control to freeze time for twenty seconds and gain some time to launch a counterattack. Rings are still consumed while it is in effect, and can be countered using Team Blast. Keep repeating this pattern to fill up the Team Blast, Super Sonic Power, which is the only way to damage Metal Overlord. After five Team Blasts, Metal Overlord will be defeated.

To acquire an A Rank for this boss battle, the player must finish it in under seven minutes.

Archie Comics
In the Sonic the Hedgehog series and its spin-offs published by Archie Comics, Metal Overlord is mentioned several times, although he has yet to make an appearance. He first surfaced in the reality created by the second Genesis Wave where his history was identical to his game counterpart. After the universe was rebooted by the Super Genesis Wave, Metal Overlord became a part of the main timeline, although his history remained the same as his game counterpart.

Trivia

 * According to some quotes in the game files, Neo Metal Sonic was supposed to have some invisibility power, presumably copied from Espio. However, this was removed for unknown reasons.
 * Though the battle employs three characters, it can be completed with only one of them.
 * At the final battle there seems to be a grammar error in some versions of the game, where Metal Overlord says: "But that's was the past" instead of "that".
 * In an official Sega forum, a member of Sumo Digital (who works on the Sega Superstars series, excluding the original) said that the designer of Metal Sonic's new vehicle for Sonic and All-Stars Racing Transformed based part of it off Metal Overlord.
 * Metal Overlord is the only boss of the 3D games who does not have a specific weak point.
 * Metal Overlord's defeat animation was later reused for Black Doom's final form, Devil Doom's defeat in Shadow the Hedgehog.
 * Like Metal Madness, in the PC version of Sonic Heroes, Metal Overlord is shiny blue instead of normal blue.