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Maybe Required Secondary Powers or Conditional Powers or Situational Sword?
You've kind of asked for multiple things, so anything on Power at a Price could apply.
Edited by bitemytailI mean the power is there but you literally cannot use it. It's like having a legendary sword but you literally cannot lift it or awaken it.
^ There are many reasons for how you cannot use a power, is what I'm saying.
But you wanted a blanket term, right?
We can never truly eradicate the coronavirus, but we can suppress its threat like influenza
I want to find a trope about a power that you cannot actually use. For example, you might had been found the legendary greatsword, but you cannot use it since it's too heavy, or you didn't remember how to use the power at all. Basically the power is here but it's dormant and you can't use it.