Creating weapons, resource, and tracker

[Fenris447]

I am in 5e and have a custom dagger I'm trying to program. The dagger consumes and stores up to 6 souls. It can consume 1 soul to cast Speak With Dead and 2 souls to cast Unseen Servant. So far here's what I have:


* Create the dagger
* Create a custom tracker and boostrap it to the dagger
* Create a custom version of Speak With Dead (removed components) and bootstrap it to the dagger
* Create a custom version of Unseen Servant and bootstrap it to the dagger


If possible, I'd like for the spells to show how many are available based on the resource (souls), and for them to in turn reduce the resource when cast.