Altavillan Blade

A mechanical blade with a discharge mechanism that propels it and its user, these rapiers are rather famous for their uses in manhunts. Their creation was backed by certain infamous families, and their shape and function was modeled for one particular style of fighting, giving it it's namesake. Though they use an odd kind of ammo, they do not make use of it for firing bullets like certain other weapons might, but instead, to shape it to fit the style of fighting it was meant to support more efficiently.

This weapon can hold up to 6 specialized ammo. This ammo is not considered as Ammunition, for spells, features and effects that would allow you or the weapon to magically produce ammunition. You may use a bonus action to load in up to 6 ammo into the weapon. This ammo can be purchased from local shops, at a rate of 200gp per 20, and it can be used to fuel the following ability:

Scorch:
Once per attack, as a free action, you can expend one of this ammo. If the attack that expended the ammo hits,  the target takes 1d6 extra piercing damage, and becomes scorched. This lasts for 3 rounds, refreshing with new applications.
For each stack of scorched on it, attacks with this weapon gain a +1 to hit, and deal an extra 1d4 fire damage against the target.
Scorched effect can stack up to 4. Every hit that would apply scorch afterwards instead adds Scorched Amplitude. At 5 stacks of Scorched Amplitude, the stacks are consumed, and the creature is paralyzed until start of its next turn. The affect creature can take a legendary action, if it has any, to end this effect. Any legendary action it would have taken on the turn this triggered is wasted.

Every consecutive ammo used past the first gives this weapon a stack of Overheat. If the weapon's attack roll is equal to or lower than the stacks of Overheat, it misfires, making the attack miss, and disabling its magical effects for the rest of the turn. Overheat drops to 0 if the weapon's Scorch ability wasn't used for one of your turns.

Proficiency with a Rapier allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: Finesse, Vex