This page contains information regarding Star Trek: Discovery, and thus may contain spoilers.
"I remain Voq, son of none, the torchbearer."
Voq was a Klingon and a fanatical follower of T'Kuvma. Outcast from Klingon society for his albino skin, Voq referred to himself as "son of none". He later assumed the name of Ash Tyler as a sleeper agent to gather information from Starfleet.
Prior to transformation Edit
In 2256 aboard the Sarcophagus, Voq volunteered to take on the role of Torchbearer after the death of Rejac. T'Kuvma initially rejected him, citing that the position of Torchbearer belonged to one of noble birth. Voq argued that his faith made him worthy – that he had been reborn through the flames of Kahless – which he demonstrated by burning his fist in a lit brazier. Accepting Voq to be a mirror of himself, T'Kuvma gave his own bat'leth to Voq and charged him with the Torchbearer's sacred duty of lighting the Beacon of Kahless. (DIS: "The Vulcan Hello")
When the Klingon High Council answered the summons of the Beacon, Voq was the first to respond to their communications. He was treated with contempt by the leaders of the Great Houses, particularly Kol. Nevertheless, Voq ardently proselytized T'Kuvma's vision of a purified Klingon Empire united against the Federation. Following their victory over Starfleet in the Battle of the Binary Stars, Voq urged the High Council again to follow T'Kuvma, whom his compatriot L'Rell proclaimed as T'Kuvma "the Unforgettable".
Voq attacked Commander Michael Burnham after she and Captain Philippa Georgiou boarded the Sarcophagus to capture T'Kuvma. However, Burnham defeated him and ultimately fatally shot T'Kuvma. Voq held his dying lord and vowed that all Klingons would rally behind T'Kuvma's memory. (DIS: "Battle at the Binary Stars")
After the battle, the Sarcophagus, commanded by Voq and L'Rell, was stranded for months with no functioning drive and lack of food. Eventually, most of T'Kuvma's House submitted to Kol of the House of Kor, while Voq was left on the wreck of the USS Shenzhou. L'rell beamed over and informed Voq that she was still on his side. She told him that she had a raider ship for him to use to reach the matriarchs of her sect to learn powers he could not yet imagine. (DIS: " The Butcher's Knife Cares Not for the Lamb's Cry")
As Ash Tyler Edit
Under the guise of Ash, Voq believed he was held captive for 227 days (almost seven months). His cellmate during his captivity was Harcourt Fenton Mudd. He was "rescued" along with Captain Gabriel Lorca by the USS Discovery, all proceeding according to L'Rell's plan. (DIS: "Choose Your Pain")
A week after this, Captain Lorca appointed "Tyler" as chief of security aboard the Discovery. (DIS: "Lethe") Captain Lorca was impressed by his skill piloting a stolen Klingon raider during their escape, as well as his impressive marksmanship in Discovery's holographic combat simulator.
Ash Tyler appeared to have suffered from severe post-traumatic stress disorder as a consequence of rape, torture, and medical experimentation inflicted upon him during his imprisonment by his Klingon captor, L'Rell. (DIS: "Into the Forest I Go") Furthermore, he harbored an internal rage towards Klingons, wanting to hurt them the way they hurt him. (DIS: "Si Vis Pacem, Para Bellum") During his mission with Burnham to place sensors in the Klingon Ship of the Dead, Ash encountered L'Rell in a room of corpses, and subsequently lapsed into catatonia. He was coached back to a conscious state by an injured Admiral Katrina Cornwell, who was a prisoner on the ship, and was able to defeat incoming Klingon warriors who were closing on their position. L'Rell was subsequently taken prisoner and transferred to Discovery's brig. (DIS: "Into the Forest I Go")
Tyler was still haunted by nightmares and flashbacks from his violations, and what was later revealed to be his surgical transformation from Voq to the Human form of Tyler. He took solace in his burgeoning romantic relationship with Burnham, who had shared trauma from the loss of her parents, her transient death, and the events from the Battle of the Binary Stars.
When the Discovery found itself in the mirror universe, Tyler, who was experiencing nightmares of surgery being performed on him, went to confront L'Rell in the brig. L'Rell recited a Klingon prayer to him, which seemed to trigger a reaction. Disturbed by this, Tyler asked Doctor Hugh Culber to perform a medical examination on him to see if he was fit for duty. Culber discovered, contrary to earlier examinations, that Tyler's skeletal structure and organs had been surgically altered and that the Tyler personality had been overlaid over that of someone else. Culber said he had to ground Tyler because he was not sure that Tyler was who he claimed to be. In response, Tyler became self-aware as Voq broke Culber's neck before accompanying Burnham and Lorca on a mission to the ISS Shenzhou. (DIS: "Despite Yourself")
While aboard the Shenzhou, Tyler and Burnham were able to gain the trust of a rebel council charged with leading the rebellion against the Empire, which included Sarek and Voq. Listening to the mirror Voq speak was enough to trigger dormant memories in Tyler's mind, which awakened the truth in him that he was, in fact, Voq himself. Having reasserted his Klingon personality, he physically attacked his counterpart, but was defeated in combat. Since Sarek confirmed, through the use of a mind meld, that Burnham's motives were altruistic, she and Tyler were allowed to return to the Shenzhou, where Burnham confronted him in her quarters and learned the truth of his Klingon origins. Tyler/Voq attacked Burnham and planned to kill her but was thwarted by the intervention of Saru. Facing execution for apparently attempting to kill the ship's captain, per standard Empire orders, Tyler/Voq was sentenced to be beamed into space. Burnham, however, operated the transporter herself to ensure that Tyler/Voq could be quickly beamed aboard the Discovery. She had hidden stolen files about the USS Defiant on his person, which the Discovery crew planned to use to return to their universe. Once aboard, Tyler/Voq claimed that Burnham should have left him to die, but Saru quickly reminded him that was not in the tradition of Starfleet. (DIS: "The Wolf Inside")
"Voq. Son of none."
"You cannot assume the birthright of a noble house. You are unworthy."
"I am worthy. not by blood... but by faith"
"I serve the light of Kahless. I am reborn in his flames."
"Open your hearts to the one who delivered this great day. Follow the light. Follow T'Kuvma."
"Your life will remembered forever by all Klingons. Your death will be a cause to unite us all."
- "The Vulcan Hello"
- "Battle at the Binary Stars"
- "The Butcher's Knife Cares Not for the Lamb's Cry"
- "Choose Your Pain" (as Ash Tyler)
- "Lethe" (as Ash Tyler)
- "Magic to Make the Sanest Man Go Mad" (as Ash Tyler)
- "Si Vis Pacem, Para Bellum" (as Ash Tyler)
- "Into the Forest I Go" (as Ash Tyler)
- "Despite Yourself" (as Ash Tyler)
- "The Wolf Inside" (as Ash Tyler)
Background information Edit
Voq was portrayed by actor Shazad Latif. Prior to the revelation that Tyler actually was a disguised Voq, Voq was credited in episodes as being played by "Javid Iqbal".  Latif chose the name of Javid Iqbal to appear in the credits in memory of his deceased father. 
Originally, CBS announced in December 2016 that T'Kuvma's protégé, then named "Kol", was to be played by Shazad Latif. In the final version of the series, Latif went on to portray Ash Tyler and T'Kuvma's protégé was renamed "Voq", while the name Kol was given to a leader of a rival Great House.  Ultimately, however, it turned out that the character of Ash Tyler was actually a construct for Voq to infiltrate Human society.