I agree that it's a bit confusing, but as stated before the correct answer is Deidara.
It's mostly due to the fact that activating a prompt mystery, forces the character to activate any passive inducing effect.
An example would be Sailor Sakura, she has two debuff removes as a passive, before her mystery she removes a layer and the second one before her standard.
Deidara induces Ignite before his mystery.
Hope that helps.