I nominate Ali Al Saachez, mercenary and Magnificent Bastard extraordinaire.
Okay, so he was in a hard time in his life, right? So he creates a war between the Kingdom of Azadistan and the annexed, ruined remains of Kurdistan, using poor, impoverished kids there as Child soldiers, encouraging them using their devout faith as God's Warriors. He even has them kill their own parents and suicide bomb places. However, the battle goes south and the Mobile Suits of the Kingdom roll on into their base and wipe out every child soldier, except for one named Soran. Ali is of course, nowhere to be found, having moved on to greener pastures.
Soran grows up and is selected by a special Paramilitary Organization called Celestial Being, the guys who build the Gundams, incredibly high-tech weapons that are years ahead of the world's militaries. Soran becomes a Gundam pilot, his faith in God shattered, and his will determined to end all conflict so nobody else ends up like him.
Ali, meanwhile, has become an ace pilot for the amoral Moralia PMC trust, a Mercenary army. And he and Soran, now under the code-name Setsuna, meet in battle once again. Setsuna is rightly enraged at Ali, and repeatedly singles him out and attempts to take his life. But Ali manages to hold Setsuna's highly-advanced Gundam at bay every time with this:
A cheap mass-produced machine. Eventually, the Four Gundams are threatened with destruction, and a shadowly client sends them reinforcements in the form of three other Gundams, piloted by three designer babies who are all amoral and vicious, only showing loyalty to each other as siblings. As things all go south and as Gundam technology is leaked to the masses, these three pilots go into hiding on an island.
Ali, meanwhile, has just killed a news reporter, who is the sister of a main character, after she was investigating Celestial Being. Understandably, this really pisses that guy off and pretty much ruins the remains of his life.
Anyway, through this Ali murders the head of the company that build the second set of Gundams, and through that approaches the three pilots while they're hiding out. He smiles and shoots one right through the chest, hijacks the Gundam, and kills the other guy in his Gundam. Later on he returns to kill off a main character before his machine is destroyed.
He returns four years later to destroy the entire Kingdom of Azadistan from the air, holds off the main characters several times, wipes the floor with everyone, sexually abuses the surviving designer baby sister whose brothers he killed, severely damages the cells of the main character through a radioactive bullet, and then beats the hell out of the brother of the guy he killed in the first season before he is finally shot between the eyes by that character.
In the final battle his opponent yells at Ali,
"Just who the hell are you?!"
Ali laughs and answers
"I'm just me!"
*shudder*
that fellow looked familiar, however, who was he?
