Activating the keyrune during battle phase

[Ashley623]

When I declare an attack...can my opponent activate the key rune s effect pay the cost and have it become a creature and block my attack? And one more thing, can I remove the last counters on the plans walker to activate one of its effects?

[Wally]

Yes to both.

By removing the last loyalty counter off your planeswalker, he/she leaves the battlefield, no longer being loyal to your cause. You may however find it in your graveyard.

RESOLVED

[Keyeto]

Keep in mind, planeswalker abilities can only be activated at sorcery speed. You can't do battle tricks with their abilities.

[Ashley623]

Kool thanks guys

[Umbra]

When I declare an attack...can my opponent activate the key rune s effect pay the cost and have it become a creature and block my attack? And one more thing, can I remove the last counters on the plans walker to activate one of its effects?

This is what makes keyrunes good (for the most part), because they can avoid things like pacifism, arrest, and mass removal.

[Rass]

Also once they are declared blocker you can still tap them and they will do damage to the blocked creature and you have a mana to spend