Hi, you have to lower enemies hp first if you want to card them.. The lower the hp, the easier it will get to succesfully card. Im not sure about Doom since I only used it in my first game and it was when the game came out... But I think it kills them instantly..
Doom starts a countdown and if the enemy is still alive when the countdown hits 0, it will in fact die. Unlike traditionally killing a monster, Doom does not take away HP or anything like that so it won't help you use abilities that rely on the health of the creature such as Card.
Yea lower the monsters hp's down and try and use card. The lower the better.
Doom is basically worthless in most cases, when you get stronger you can kill foes alot quicker with attacks than dooming something. In most cases even high hp monsters can be demi'd down before doom works.
--- I am outraged! I am outraged beyond words! Yet...I have something I want to say..