Martial Trick Weapons
Trick weapons are clever inventions designed by the members of the Incendiary Guild. They are called “trick” weapons because each weapon can be transformed in the heat of battle to provide its wielder with an expanded array of options with which to fell the horrific beasts that haunt Krevborna. Trick weapons are rarely sold to private individuals; rather, they are either bestowed upon those who have proven themselves to be allied with the Incendiary Guild or passed from one hunter of the dark to another.
Combo. On a critical hit with this weapon, you deal the damage listed for the combo property of its current mode instead of rolling double damage dice. You choose the damage type of a critical hit from a weapon with the combo property from the types of damage it is capable of dealing. For example, a critical hit from a lashing cane can deal either bludgeoning or slashing damage.
A weapon with a ranged transformed mode can only deal extra damage from its combo property in melee combat; a critical hit that occurs outside of melee range deals critical hit damage as normal. For example, a critical hit from an arrow fired from a yeoman blade in its transformed mode deals 2d6 piercing damage. A critical hit with a trick weapon with the ammunition property must expend one piece of ammunition to deal its combo damage.
Transform. You can use a bonus action to transform a trick weapon from its normal mode to its transformed mode or from its transformed mode to its normal mode. When you attack with a trick weapon, you use the damage and properties of its current mode.
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All of the above was inspired by the weapons in Bloodborne, of course. If you need image inspiration, it probably plays out like this: beast saw = whirligig saw, church hammer = kirkhammer, duelist rifle = reitterpallasch, internment blade = burial blade, kirk pick = church pick, lashing cane = threaded cane, serrated cleaver = saw cleaver and beast cutter, stalker axe = hunter axe, temple blade = Ludwig's holy blade, warden pike = rifle spear, wild claw = beast claw, yeoman blade = Simon's bowblade.