Daisuke Sekimoto
On February 27, 2011, Harashima unsuccessfully challenged Dick Togo for the KO-D Openweight Championship. On April 6, during a four way match against Antonio Honda, DJ Nira and Michael Nakazawa, Harashima was attacked by the three other wrestlers before being saved by his alter ego Hero!. On May 4, Harashima and Hero! unsuccessfully challenged KO-D Tag Team Champions Gentaro and Yasu Urano. On May 21, Harashima reached the finals of the 2011 King of DDT tournament but lost to his long time rival Kudo. On June 24, Harashima and Hero! won the KO-D Tag Team Championships from Kenny Omega and Michael Nakazawa. The duo would lose the titles to Daisuke Sekimoto and Masa Takanashi at Ryōgoku Peter Pan 2011. In August, Harashima's other alter ego, Darkside Hero!, debuted and turned on Harashima alongside Hero!. Harashima defeated both men in singles matches; Hero! on September 18 and Darkside Hero! on October 5. On November 27, Harashima unsuccessfully challenged Kudo for the KO-D Openweight Championship.