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You're absolutely correct. A "must" keyword is planned, according to this post by wololo. I don't know hard this will he to implement - it might be possible to reuse the code for "may", but one potential complication is that the code needs to count the legal targets, and then actually force you to choose one (without a way to cancel the the action, which usually exists by pressing Cross), or proceed if (but only if) there are no legal targets.Btw, just to prevent misunderstandings, there is no "current way of coding them with the target= line", all such cards were taken out for exactly the reason you give, they don't work. If you spot such cards in the official release, then that's a bug, please report them so that we can remove them.

