Kalen was first created on December 1, 2001, the band initially consisted of Hisana (vocal) Erize and Hiroshi (guitars) and Noa (bass). However, this line up did not last very long. The official beginning date of Kalen's 'true' activities was March 2002, when the band played their first live with their a new line up: Nao (vocal), Erize and Setsuki (guitars), Takaya (bass) and Shunna (drums).
Their first demotape, Solve, came out on August 17, and their first maxi-single, flow~, was released in December. On New Year's Eve they took part in the Matina label's last concert, which took place at the On Air Osaka.
In March 2003, one of their songs was featured on LOOP ASH's omnibus album LOOP OF LIFE III, and in April the band joined Kisaki's new label, Under Code. Their first release on the new label came out in July, and in September their song appeared on UC's first omnibus - High Style Paradox 1.
January 2004 brought more good news: on the 10th, they released their first full album Reset ~a revolving lantern~, which was followed up by their first one-man live at the Esaka Boomin Hall at the end of the same month. Their first video tape was distributed during that show.
The pace of their career from here on became more brisk. In February, they distributed their CD entitled tomadoi during lives and their tour actually in reality began in May. Immediately after the tour the band released a mini-album entitled Actually. Throughout 2004 their songs appeared on 3 omnibus albums.
During this time the band hardly took any breaks from performing live. At the beginning of July Kalen held a two-man with Mar'derayla, and on August 25 they played their second one-man live, during which a special single and a second video tape were distributed. In September they held two connected two-man performances: on the 23rd Kalen performed with Panic*CH and on 26th with... Panic Channel. To round off the year the band toured with alice nine. from November though the end of December.
2005 began with even more performances. During their live of January 30th, fans were able to buy Kalen's upcoming single, utakata no kokoro, in advance, whilst a CD containing live version of Actually was distributed for free.
March witnessed the release of a mini-album, and during April's live commemorating its release the band's third VHS was given out for free. In the same month Kalen released a coupling CD with Luvie, Clavier and Gift, before the bands set out on a promo tour which ended on May 17th at the Shibuya O-WEST. Two maxi-singles came out in August and September, and in October the band played two one-man lives. Before the year ended they also participated in a few Under Code events, and they entered 2006 performing at an all-night New Year's event at the Holiday Umeda.
Kalen's bustling popularity made the news of late 2005 come as a shock to everyone - the announcement stated the band would be ceasing activities in February 2006. Nonetheless, Kalen continued to give their best until the very end. A special performance to celebrate Takaya's birthday was held at the beginning of 2006, two special best-of albums were released in January and February. In February, Kalen embarked on their last one-man tour, during which their last single, Proud, was distributed. The members of Kalen played their last live together on February 27 at the Holiday Umeda.
After the dissolution, Setsuki joined 176BIZ, while Shunna joined Dari - which is a band made up of ex-Sugar Folkfull members.