Ianto Jones

Ianto Jones is Torchwood Three's "support man". His job entails manning the reception desk in the Information Centre that acts as a cover, administering the computer systems, serving coffee and tea, receiving reports and cleaning up loose ends – such as covering up deaths and destroying information that could trigger retconned memories. While he primarily functions as an administrator for the team's headquarters, Ianto does frequently accompany the team on investigations.

Early life
Ianto was born on 19th August 1983. (TW: Fragments) He is from Cardiff. (TW:From Out of the Rain) Ianto's father, a master tailor, had a shop in Cardiff; he enjoyed taking his son to the cinema. (TW:Something Borrowed, From Out of the Rain)

At Torchwood 1
Before joining Torchwood 3 in Cardiff, he worked in Torchwood 1, based in Canary Wharf, London. During the events of Doomsday, his girlfriend, Lisa Hallett, was partially converted into a Cyberman. Confident that the cyberconversion process could be reversed, Ianto smuggled Lisa to Torchwood Three, hiding her in the basement, until a "cure" for the partial cyber-conversion could be found.

Joining Torchwood 3
When Ianto helped Jack with a Weevil, Jack was surprised that the young Welshman knew what it was. The next morning found Ianto waiting outside of The Hub with a drink for Jack--and a request for a job. When Jack demurs, saying that there are no vacancies, Ianto then asks for help catching a pteranodon that he found. He and Jack catch it and Jack offers Ianto a job. (TW: Fragments)

With Torchwood 3
Ianto hacks into Gwen Cooper's computer and erases a document containing information about Torchwood. Aside from his quiet efficiency, little is initially revealed of Ianto's personality. He is the only Torchwood agent not shown as having taken an alien artifact home (TW: Everything Changes)

However, Lisa's Cyberman personality asserted itself over her human emotions and she tried to take over the Hub, intending to use it as a staging area for a new Cyberman army. Viewing her incomplete conversion to cyber form as "flawed", Lisa transplanted her own brain into the body of a pizza delivery girl to begin the process anew together with Ianto, but her new body was shot and killed by the rest of the team (TW: Cyberwoman). The others appear to take the quietly efficient Ianto for granted; they pay little attention to him before the mayhem starts. When interrogated on what else he is hiding from the team, Ianto bitterly replies that he just "cleans up their shit... no questions asked" and that they never ask him about his life. At one point he calls Jack a monster and threatens to leave him to die if given the opportunity to save him. The Cyberwoman incident places strain on his relationship with the rest of the team. Ianto is "temporarily suspended from active duty" and is allowed to return to work four weeks later with Jack's tacit approval. ("The Captain's Blog" BBCAmerica)  In an attempt to show he has put the incident behind him, Jack tries to be friendly and even pats Ianto on the back (TW: Small Worlds). Although the conversation about the teams' last kisses reveals that there is still some lingering tension between the two over the incident. (TW: Countrycide)

Ianto starts to take a more active role. He describes to Toshiko Sato his inability to comprehend the adrenaline rush she and the other Torchwood members share in the face of danger. Like Gwen, his humanity is highlighted, but he makes attempts to actively fight alongside his colleagues. (TW: Countrycide)

Ianto is able to calculate the amount of money for food that Emma has left, quickly in his head, even when she grabs multiple chocolate products after finding out that she has some money left over. (TW: Out of Time)

It is hinted that Ianto may be having a sexual relationship with Jack. This is supported by an instant messenger conversation between him and Jack on the Torchwood Institute website that suggests that like teammates Jack, Toshiko and possibly Owen and Gwen, Ianto is bisexual; Ianto also explains he would not resurrect Lisa with a second resurrection gauntlet. This is confirmed in the first part of the season finale, "Captain Jack Harkness", when Owen makes remarks about the sexual nature of Ianto and Jack's relationship and the conclusion, "End of Days" when Jack kisses Ianto after returning to life. (TW: They Keep Killing Suzie)

Ianto and Owen spar for leadership of the team with both Jack and Toshiko trapped in the 1940s, although Owen asserts he is second-in-command, replacing Suzie Costello who previously held the title. However, Ianto displays authority in Jack's absence that Owen was not aware he had. Ianto goes as far as to shoot Owen in the shoulder to prevent him using the Rift Manipulator. In "End of Days", an apparition of Lisa convinces Ianto to side with Owen against Jack. After believing Jack was dead, a distraught Ianto breathes in the scent of his coat, in a scene reminiscent of Brokeback Mountain, and seeing Jack alive at the end of the episode, the two kiss upon reunion. (TW: Captain Jack Harkness)

After Jack's disappearance he, along with the rest of the Torchwood Three team, was dispatched on a "wild goose chase" to the Himalayas by Mr. Saxon.

Ianto has apparently taken on a more active role in the Torchwood Team, taking part in field missions to compensate for the absence of Captain Jack. (TW: Kiss Kiss, Bang Bang) When Jack returned, he asked Ianto out on a date, which Ianto accepted. This is followed by another on-screen kiss between the pair. (TW: To the Last Man). The existence of the relationship is confirmed verbally in a conversation Ianto has with Martha Jones (TW: Reset) and in another conversation Ianto has with Owen Harper (TW: A Day in the Death).

It is revealed that Ianto keeps a paper diary, which he uses to write down interesting Rift activity as well as more personal concerns. When he confronted 'Adam' about his role in the Torchwood team, the alien gave Ianto false memories of killing three women, which affected him deeply. He was eventually able to rid himself of these memories when Jack retconned the team to purge the alien's influence. The entire Torchwood Three team lost a total of 48 hours. (TW: Adam) Ianto reveals that his father was a master tailor, the first real clue to Ianto's background we have had yet in the series. At the end of Something Borrowed is the first public display of Ianto and Jack's relationship, when they dance together at Gwen's wedding. (TW: Something Borrowed) Ianto tells Gwen and Owen that he used to go to the Electro movie theatre with his father as a child. (TW: From Out of the Rain)

When the team is lured to an abandoned warehouse, it is soon discovered to be a trap laid by John Hart and the team ends up trapped. (TW:Fragments) The team eventually escapes alive and makes it back to the Hub where rift activity is located in three separate locations. He and Toshiko make their way to the central server building for a phoen company where they are confronted by three cloaked men with scythes who advance on the duo of Torchwood agents. Toshiko and Ianto quickly dispose of them with their pistols and later make their way to the roof of the building to observe a series of explosions rock Cardiff. When it is revealed that the city's nuclear power station is entering a meltdown, Ianto and Toshiko were originally on their way to intervene until a group of Weevils swarmed past them and Owen decided to take up that task himself, allowing the duo to return to the Hub where they were subsequently locked in Weevil cells by Gray. They are later freed following Gray's capture at Jack's hands and Ianto later discovers the final logout of Toshiko following her death at Gray's hands and mourns for the loss of both Owen and Toshiko. (TW: Exit Wounds)

An unknown amount of time later, the Earth is stolen by Davros and the New Dalek Empire and transported to the Medusa Cascade. Ianto ends up assisting Gwen and Jack utilise the Rift Manipulator in conjunction with Mr Smith to boost the signal of Martha Jones' superphone in order to contact the Doctor. This plan suceeds and the Doctor makes his way to the Earth. At this point, Jack obtains the missing digit of a code for his Time Agency wrist strap and leaves Ianto and Gwen to meet with the Doctor. After he leaves, Gwen and Ianto are confronted by a Dalek entering the Hub and open fire with machine guns. (DW: The Stolen Earth)

Donna's World
If Donna Noble had turned right, instead of left, stopping herself from ever meeting and saving the Doctor, Ianto (along with Gwen) died in order the stop the Sontaran battlefleet invading Earth (DW: Turn Left). However, when the history of this world was changed back to normality, the actual happenings of the event returned, meaning it was Luke Rattigan who destroyed the fleet, in the place of Ianto and Gwen.