Matthew Shrieve

General Matthew Shrieve was a corrupt general of the U.S. Army. Fearing China would eventually bring the end of America, Matthew plotted China's downfall with a bio-weapon which killed thousands in Hong Kong including Akio Yamashiro. In rage, Matthew was executed by Akio's father, Maseo, but only after hours of painful torture by Oliver Queen.

Biography
After Oliver Queen stopped Chien Na Wei from selling the Omega, General Shrieve told Oliver he had to return to China for a debrief, in return, he would allow Oliver to go wherever he wished. Upon finalizing Oliver's debrief, Matthew kept his word and allowed Oliver to go anywhere he wished, but he had to go to Japan with the Yamashiro's first. It later was revealed that he broke his promise and ordered men to hunt down and kill Oliver and the Yamashiros. It turns out, while Oliver is infiltrating an A.R.G.U.S. field house, General Matthew had held Amanda Waller prisoner. He thought that Hong Kong was a military threat and was planning on using the Omega to destroy the city.

After Akio was subjected to the virus, Maseo and Oliver tracked down Matthew where they forced him to procure the cure for Akio. Unfortunately there was never a cure, as Matthew revealed that Maseo had in fact took insulin for Matthew's diabetes. Upon his trickery, he subdued Oliver with snipers.

Due to Akio's death caused by the virus, Oliver tortured Matthew for hours and left him unconscious until Maseo shot him in the head, killing him instantly.

Legacy
Despite his death, Matthew's actions was what indirectly led Maseo Yamashiro to join the League of Assassins, becoming known as Sarab. His brutal death made Oliver believe he was torturing him for justice but eventually realized it was vengeance and served as a vital growth point to help him distinct justice from vengeance.

Personality
Shrieve was a manipulative liar with little regard for the people he hurt, justifying it with the belief that he was serving his country. He attempted to kill Oliver and the Yamashiros in order to tie up loose ends despite the services they had done for him. He was probably as sociopathic and immoral as Amanda Waller is, if not worse, in his pursuit of his goal to wipe out China that he believes to be a major military threat using the Alpha-Omega bio-weapon that would kill thousands of innocent people. In his final moments, he had absolutely no guilt or remorse for his actions. Despite his horrendous actions, he did genuinely believe his actions wold benefit the United States by crippling China.

These negative traits of his, was what led to Matthew's painful yet deserved torture at the hands of Oliver Queen, and deserve death at the hands of Maseo Yamashiro.

Season 4

 * "Green Arrow" (mentioned)

Behind the scenes

 * In the DC comics, Matthew Shrieve is a military lieutenant who leads a paramilitary squad known as the Creature Commandos, comprised out of cinematic monster themed super-heroes.
 * Matthew is portrayed in contrast to his DC comic counterpart; originally he was a hero, but in Arrowverse he is an immoral, sociopathic villain.