Bule has the forced ability of corrupting one target unit at the start of the turn. Does King Kazador's card text that says it must take 3 resources to target him with card effects kick in versus Bule's ability?
On a related note, What about Festering Nurglings? "Forced: After this unit enters play, corrupt one target unit in any player's corresponding zone" I'm assuming the answer to my question about Bule and King Kazador would apply here too.
Anything that targets specifically (using "target" in the wording) would have to pay 3 to hit Kazador. So if the only Units out are Bule and Kazador and you don't have 3 resources saved, you'd have to corrupt Bule with his own ability (of course, would restore him in your Kingdom Phase).
Also, I had a game where my opponent said if I played Festering Nurglings in the battlefield and his battlefield was empty, then I would have to corrupt one of my units in my battlefield because of the forced ability. I argued that the word "corresponding" would mean it wouldn't apply to my own zone, but he checked the rule book and looked up the definition of "corresponding" and said that yes, the festering nurglings forced effect would also apply to my own battlefield zone if there was no other target in the opponent's battlefield zone to target.
Is this so?
I think there is a difference in corresponding. Some, like the rule paragraph on corresponding zone talk about "opponent's corresponding zone". But Festering Nurglings is applicable against "any player's corresponding zone", which includes the player playing the FN. Could the FN have been worded in accordance with the rules, i.e. "each player's corresponding zone" (like Grimgor)? Sure. Still, any player's corresponding zone = each player's corresponding zone as I see it (at least in this instance).