Kai and Sehun of K-pop boy band EXO will debut as a new duo, EXO-KASE, on Dec. 1 with their first EP, “Waking Up The City,” their agency SM Entertainment said Wednesday. The two members were both born in 1994. Fans have long paired them under the nickname “94-liners,” a reference to the Korean fan practice of grouping idols by birth year. The agency billed the act as a “visual performance unit” that pairs Kai’s intense, “hot guy” charisma with Sehun’s chic, “cool guy” image. In K-pop, a unit, or sub-unit, is a smaller group formed by members of an existing band to release music with a concept separate from the full group. EXO debuted in 2012 and has previously released music through units such as EXO-CBX and EXO-SC, the latter of which included Sehun. The EP, also known in Korea as a mini album, contains seven tracks in a range of moods, including the title track of the same name and a solo song by each member, according to the agency. Sehun talked about the unit at EXO’s encore concert last week. “More than anything, the performance is incredible,” he said.