, titled "Legion" (Japanese: 双闘（レギオン） ), is the second episode of the Legion Mate arc (Season 4) of Cardfight!! Vanguard , originally airing on March 16, 2014 . This pivotal episode introduces a revolutionary game mechanic and focuses on the struggle to restore the forgotten memories of the series' protagonist, Aichi Sendou . Plot Summary
: Introduced as a power allowing two units to share the Vanguard circle simultaneously. Cardfight!! Vanguard Episode 165
: This episode marks the second entry in the Legion Mate-Hen series, which focuses on Kai as the lead protagonist searching for the missing Aichi . titled "Legion" (Japanese: 双闘（レギオン） )