It seems pretty strong, although is hard too say if it is TOO strong. There are several tweaks that can be done, like allowing to discard any Treasure instead of just Copper (though I would do this right away, because it does not seem to change the power level in a significant manner), or capping in some way the number of times per turn you can attack with it.
The thing about Torturer is: $2 maybe comparable with +3 Cards in the vacuum, but neither attack is really strong if you attack only once (and the penalty of gaining Copper dilutes on time because it is less important as the game goes on, the Curse at least is -1 VP at any moment you choose to gain it). To attack a lot, you need an engine. And if the point is attacking a lot, you need draw better than more money (because the payout, at least initially, is mostly the attack itself). Torturer is terminal, but it gives you the draw. Charter does not help you at all to make an engine that attacks a lot. Spamming enough Charters and Terminal draw to be able to attack twice per turn is probably really slow and a simple terminal draw + BM will outplay it easily.
