Grapnel Gun

 is a device designed by Hotaru Yanma (non-canon) and by Ryūken Senju (canon). It is one of their main gadgets and have been observed to be used quite frequently by the respective owners. It can be used for multiple purposes like transport and even in combat. It allows him to easily grapple to the top of buildings and towers.

The grapple device also allows Hotaru/Ryūken to pull off vent coverings on out-of-reach walls, clear objects out of his way that he can't reach normally and make enemies drop their weapons. It also lets Ryūken pull thugs off ledges and in combat it can pull them towards him until they eventually fall over.