Deathstroke

Deathstroke the Terminator (Slade Wilson) is a revered supervillains, and sometimes anti-hero. He is a trained mercenary and assassin who first fought with the Teen Titans, then came to be known as one of the greatest villains in the superhero world.

Background
Slade Wilson started his career as a young man in the U.S. Millitary, he proved to be a successful recruitand expert in, while under the trainning of his captain, Adeline Kane. Sometime when Slade continued working with the army, Adeline was pregnant gave gave birth to their first child, Grant. Before coming home to see, Slade was asked to volunteer in an experiment, to which he accepts...after being told that it was some treatment that would resist enemy truth syrums. However, it turns out that the experiment was actually to create super soldiers, as it gave him enhanced strength, speed, agility reflexes, and overall senses; as well as regenerative healing by supercharging his adrenaline. At that same time thou, it first made Slade dangerously aggressive, thus they had to sedate him.

After a while, Slade soon recovered from his comma and the army discharged him, thus the experiment abonded. Slade then became a big game hunter, and was then legally married to Adeline and had a second child, Joeseph.

At the same time thou, Slade was working in secret as a mercanry, to which he uses his millitary expertise and now enhanced abilities to his advantage.

Sometime later, Joeseph was then kidnapped by a terrorist, who was about to kill him via slitting his throat. Slade, as Deathstroke, tired to save his son; which he died but the terrorist still cut a bit of his throat which resulted in Joeseph being a mute. In raged by his actions, Slade's wife, Adeline, shot him in the eye trying to kill him; a big price to pay.

Years later, after his then recognition as a highly skilled mercenary assassin, he was hired by a criminal organization known as, H.I.V.E., offered to hire him to murder The Teen Titans, to which Deathstroke refused however. So instead they inlisted his oldest son, Grant, subjecting him to the same super soldier syrum, and naming him, Ravenger.

Thou Slade as a father warned him not, Grant took up the offer, and sometime later was killed in the process. This prompted Deathstroke to further accept The Hive's offer to kill The Titans, as a means of completing his deceased son's contract to avenge his death.

While doing so, Deathstroke's war against The Titans also caused him to come into conflict with other, more adult superheroes, including The Justice Leage; and with that his name was made nutorious, as one of the world's most deadliest fighters, as Deathstroke.