Lee Jae Jun, also known as Marcus and formerly known as Maru, is a South Korean singer, dancer, former member of C-CLOWN (씨클라운) and TREI (트레이) and current member of the duo JT & MARCUS (제이티 앤 마커스) and TAN (티에이엔). He graduated from Heungdeok High School and is enrolled at Cheongju University.
He made his debut in 2012 (under the stage name Maru) as C-CLOWN's lead rapper, lead dancer, vocalist and maknae with their 1st mini-album "Not Alone". The group was managed by Yedang Entertainment (now known as Imagine Asia, 이매진아시아). In 2015, the agency announced C-CLOWN was disbanding, so he decided to leave the agency. He began using his birth name, and in 2017, he joined Banana Culture Entertainment.
He re-debuted in 2019 as TREI's leader, main dancer, and lead vocal and visual with their 1st mini-album, "Born". Unfortunately, the group was not successful and disbanded in mid-2020.
In 2021, he joined MLD Entertainment and re-debuted for the third time as part of the duo JT & MARCUS (alongside former TREI member Jun Tae or JT) with their 1st single, "Dear You". They occasionally release a new single and have provided an OST for the drama "Going to You at a Speed of 493 km".
Later that year, he entered the singing survival show "Extreme Debut: Wild Idol" and finished in 5th place, earning a spot in the project group TAN as the main dancer, sub-vocalist and visual. They debuted in 2022 with their 1st mini-album "1TAN". They released a pre-debut Japanese mini-album in late 2023 and have plans to officially debut there in 2024. He is also starting to become interested in acting.