|This article is about a/an ally in GoGo Sentai Boukenger.|
Shirou Masaki (柾木 紫郎 Masaki Shirō, 4)
One of Satoru's ex-partners who went on an expedition with him years ago. While searching for a Precious, Satoru accidentally set off a trap which created a ring of fire that neither he nor Kyoko could escape and Satoru could not reach them. Satoru swore to get help and rescue them, but the trap triggered an explosion, killing Kyoko and Masaki before Satoru could even leave to find help. Later on, Rei tricked Satoru into believing that Gai was Masaki, still alive, so he could shoot him with the Fighter's Crossbow. Eventually Satoru saw through the illusion and went defeating Rei. Portrayed by Yusuke Murakami (村上 裕亮 Murakami Yūsuke).