MORTAL KOMBAT (in brief)
It is known that his father, a former member of the Shirai Ryu, forbade his son from joining the clan, as he did not wish for his son to live the life of an assassin. However, Hanzo joined in spite of his father's wishes in order to provide his wife and son with a comfortable life.
Now Scorpion is a hell-spawned spectre, inexorably seeking vengeance against those responsible for the destruction of his clan and the death of his own family. Despite his malevolent appearance, he is not inherently evil. He joins the forces of evil when promised a means of resurrecting his clan on Earth, or the chance to inflict his wrath against those who butchered them. Scorpion has also (indirectly) assisted the game's protagonists to fulfill these motives.
Although Scorpion is often strict and wrathful, at times he shows a caring side and is very honorable.In the original timeline, when he discovers the Sub-Zero in the second tournament isn't Bi-Han and in fact his more merciful brother, Scorpion vows to protect Kuai Liang instead for killing his kin. In the second timeline, Scorpion truly intended to spare the first Sub-Zero in exchange for the resurrection of his clan, but Quan Chi prevented this. Most notably, in the Mortal Kombat X Comic, it's shown he took in victims and survivors of the Netherrealm War into his iteration of the Shirai Ryu to now protect Earthrealm while also raising Takeda Takahashi.
Before the ninja of vengeance could finish his cold rival, he is transported into another world, a very new place that he is unaware of. In the ending, Trigon accuses scorpion for leaving his army (unaware that Hanzo is NOT from the DC universe) and both had a massive duel in hell. Scorpion came out as the victor and takes control of the demon king's army, using it to conquer the earth. It is unknown if this non-canon timeline would continue in Injustice 2, falling into sub-zero's story.