Danny Pink
Rupert "Danny" Pink was a sergeant in the British Army, who later became a mathematics teacher at Coal Hill School.
Biography
Childhood
As a child, Rupert lived in West Country Children's Home in Gloucester for some time. One night, he had a nightmare of someone under the bed grabbing his ankle, and he met the Twelfth Doctor and Clara Oswald for the first time. They encountered a figure which the Doctor believed might be a creature that hid under the bed. The three of them turned their backs so the creature could leave unseen. After it departed, Clara attempted to put the child at ease by placing toy soldiers to guard under his bed. She designated one of them — which Rupert had called "Dan the soldier man" — as the one in charge: a soldier so brave, he didn't need a gun. Rupert's mind was then scrambled by the Doctor to prevent remembrance of this encounter. He instead would only recall a dream where he was "Dan the soldier man". (TV: Listen)
Military career
Later in life, Rupert started going by the name Danny and joined the army, where he performed a number of humanitarian tasks, such as building wells, alongside traditional military work. (TV: Listen) He was a sergeant and served five years both at home and in Afghanistan. (TV: The Caretaker) Following his exit from the army, Danny became distressed when mention was made of him having killed while a soldier. (TV: Into the Dalek)
Maths teacher
Despite leaving the army, he established the Coal Hill Cadet Squad when he began working at as a teacher at Coal Hill School. It was here that he was introduced to Clara Oswald by Mr Armitage. She invited him to join her at Kathy's retirement party after work that day, which he initially declined — an act he immediately regretted. While reviewing this awkward moment to himself, Clara overheard him. Although this further embarrassed him, Danny gratefully accepted her offer to grab a drink together. (TV: Into the Dalek)
The two went for a drink at some point later, with mixed results. The couple argued several times, and Clara left twice. After an adventure with the Doctor, Clara came to Danny's flat later that night, and, after the two apologised for their behaviour, they kissed for the first time. (TV: Listen)
Despite these difficulties, the two continued dating. (TV: Time Heist)
Afterwards the Twelfth Doctor re-met Danny Pink as an adult, insisting that he was a PE teacher even after Danny said he was a maths teacher. (TV: The Caretaker)
Legacy
Eventually, he became the great-grandfather of Orson Pink. (TV: Listen)