Of Swords and Parasols

For once that isn't a Gunlock screwup -- it's semi-obscure manga canon from Petit Burial that didn't get an official English release until Reload 8. Nyoi-bo and Shakugetsujou are weapons possessed with demonic power that had been sealed away in a jar in Keiun Temple's treasury; Gojyo and Goku broke the jar horsing around when they were supposed to be cleaning, and now the weapons are bound to them for life. (Which sort of josses the common fanon that all youkai can summon weapons from hammerspace, but at the same time that now makes the earlier scenes where Goku and Gojyo are fighting bare-handed in situations where a weapon would have been handy a bit more understandable...)