Here's my mechanic "
Concentrate". It's an ability for equipment (or creature I suppose) that gathers energy for each turn it isn't used, in the form of Concentration counters. These counters can then be used for extremely powerful abilities, usually with
dangerous downsides. The Tome, for instance, draws cards at the cost of life, and the longer you
concentrate, the more it will do per use. It's important to note that there's no way to take counters off the tome, so if you put too many counters on it, it can kill you (hence the curse).
The staff builds into a powerful board wipe and damage spell, but again, with no way to remove counters from it, it becomes
dangerous if the number of counters gets too big.
Finally, the ring is suppose to be the source of the curse and exemplifies it in it's most concentrated form. A single turn of
concentrate gives 5 counters, which can be used at instant speed to kill a creature (and potential the wielder). However, saving up those counters until there are 20 can be an instant game winner, but if you fail to finish them off in that one shot, the ring will ill you in it's place.
As written, the ring is more exploitable than intended, largely due to not being able to make the font small enough to fill in the loopholes.