Ashigara is supposed to wear the same clothing as Kintarou, the semi-legendary retainer of Minamoto no Yorimitsu. Kintarou was raised by a witch who lived in Mount Ashigara, and is also known as Sakata no Kintoki, who appears as a Berserker servant in FGO and served as template for Sakata Gintoki.
I climbed Mt. Ashigara (Kintoki) in January, spectacular views over Fuji and Hakone. Take my advice and do not climb from the Hakone side, it's steep as hell, easy for a fast descent though.