Klaine

Klaine is a relationship between Kurt Hummel and Blaine Anderson.

Canon Relationship
Kurt and Blaine meet in Never Been Kissed, when Kurt spies on the Dalton Academy Warblers, due to a suggestion made by Puck during a meeting of the New Direction boys about how to beat the girls in the Boys vs. Girls competition. Blaine and Kurt have instant chemistry and soon develop a friendship. Blaine gives Kurt advice on how to handle Karofsky's bullying, and goes to Kurt's school to confront Karofsky about his actions, but when the bullying becomes unbearable, Kurt transfer to Dalton Academy and joins The Warblers, resulting in him and Blaine continuing to grow closer. Blaine often acts as a mentor and source of courage for Kurt, before making the transition into a romantic interest.

In A Very Glee Christmas, Kurt reveals to Will that he is in love with Blaine, and that Blaine is actually gay. The two perform their first duet, Baby, It's Cold Outside. Then in Silly Love Songs, Kurt admits to Blaine that he has feelings for him. Blaine confesses that he has no idea what he is doing when it comes to romance, and the two agree to stay friends. They remain just friends until Blaine realizes he is in love with Kurt in Original Song (when Kurt sings Blackbird by The Beatles). This is the episode in which they share their very first kiss, and it is assumed that they start dating very soon afterwards. In the episode New York Blaine tells Kurt that he loves him, to which Kurt replies that he loves him, too. Their relationship is taken to the next step in Season Three where Blaine transfers to McKinley because he can't stand to be apart from the person he loves.

Kurt and Blaine share loving looks during some songs and rarely fight, having had had three fights during the course of their relationship so far (The First Time, Dance with Somebody and The Break-Up). They have been dating for over a year, their one-year anniversary was on 15 March 2012. They also lost their virginities to each other in Season Three in the episode The First Time.

In Season Four, Kurt and Blaine's relationship is tested when Blaine convinces Kurt to move to New York in The New Rachel. They maintain their long distance relationship successfully at first via skyping and texting, but with conflicting schedules, things start to slide quickly. In The Break-Up, Blaine surprises Kurt by showing up in New York early. During Blaine's acoustic performance of Teenage Dream, he becomes very emotional, which Kurt notices. Eventually, Kurt asks Blaine what the problem is, resulting in Blaine telling him that he was with someone else back in Lima (presumably Eli.C). Kurt leaves heartbroken and ends up giving him the silent treatment. In The Role You Were Born to Play, Blaine admits to Sam that since the break-up, he hasn't been the same and is afraid that he lost the love of his life.

Now, in the first episode of Season 5, Blaine convinces Kurt to get back together with him, after finding out that the relationship between Kurt and his (former) boyfriend Adam Crawford didn't work out, after which they sing Got To Get You Into My Life, a song prepared by Kurt and performed with a marching band. Blaine then asks the New Directions, the Warblers, the Haverbrook School for the Deaf and Vocal Adrenaline to aid him in his proposal to Kurt by singing Help!, which they all readily agree to. Burt drives Kurt to Dalton Academy, where Blaine and all the choirs proceed to sing All You Need Is Love, along with Rachel, Mercedes and Santana, before finishing at the very staircase on which Kurt and Blaine first met. Blaine gives a heartwarming speech about his and Kurt's love, before asking Kurt to marry him, which, through tears, Kurt agrees to.

Trivia

 * Shippers of this ship are often called "Klainers".
 * Kisses between them are often called "Klisses" by the fandom.
 * Sex between the couple is known as "Klex" in big parts of the fandom.
 * Cuddles they share are known as "Kluddles" to many fans.