[@Automaton][@knighthawk][@Raijinslayer]

Kind of like the heritage system, 'houses' owning certain demon blades could prove for some interesting group and role play dynamics to be sure.

As for Demon blades being other weapons, could work but since a lot of things do not have scabbards need some other way to keep the miasma in check.  Having all Katanas, or at least swords, would be easier to implement.

Course if we impliment a system  as knighthawk suggested I suppose it would be easier to use other weapons.  In that case scabbards would not be the item to keep the weapons in check and something else would be used.  So for example a special tailsman on the handle of a weapon might keep the corruption in check most of the time but in times of extreme use it cannot hold back the large flow of bad energy which then infects the user.  If you are really crazy then you could even take the tailsman off and use the weapon without worrying about the overflow of evil energy but you sure won't last long.