Karn liberated

[Richardalcala]

{karn liberated} can I target a player with no cards and hand with his plus 4 ability. 

[Kaleo42]

Yes, it will return will "fail to search/ find" and result in no card actually being exiled.

[Richardalcala]

Is there a ruling for this? I could not find one.

[Cal8301]

Don't need one adding the lotalty counters is the cost so what happens with the effect is not important.

[BlackJester]

Correct. As long as the player is a legal target when you activate, Karn will get counters.

You targe the player, not their cards in hand.

[Kaleo42]

Don't need one adding the lotalty counters is the cost so what happens with the effect is not important.

Right idea, but not totally true. You do need a legal target to activate the ability.

[Richardalcala]

Not sure about that causes had {jace, memory adept} my opponent hex proff via {witchbane orb}. So I asked the judge if I could target him and nothing happen would jace still plus one. He sayed since my opponent was not a legal target I couldn't. He did say I could draw one than mill myself one. I know we have talked about this before.

[Maximo]

A player having hex proof from {Witchbane Orb} does not equal a player having no cards in hand. The ability cares about targeting the player, not target hand with cards in it. You can still tap a creature that's tapped with spells like {Frost Breath}, you know?

It doesnt gain immunity from tap effects, and having no cards in hand doesn't make you immune to discard effects.

[Kaleo42]

A player having hex proof from {Witchbane Orb} does not equal a player having no cards in hand. The ability cares about targeting the player, not target hand with cards in it. You can still tap a creature that's tapped with spells like {Frost Breath}, you know?

It doesnt gain immunity from tap effects, and having no cards in hand doesn't make you immune to discard effects.

Well put

[Richardalcala]

Now it seems like we are talking about two separate things. I get the karn question. It doesn't target the card in hand it target the player. However if a player has hex proof he can't be a legal target. That is what we are all saying  I think just in different ways.

[Maximo]

To plainly answer your original post, yes, you can target a player with no hand with Karn's +4 ability.

To answer what seems to be your new question, no, you can't target a player who has hexproof with any abilities that say "Target player", including Planeswalker abilities. You can still target yourself to up your loyalty though, unless you have shroud somehow.

[Richardalcala]

That is what I was trying to say we just keep saying the same things over again. 

[Maximo]

... Then the question is resolved, gavel, the end.