Whats Your Ace/Trump monster card in Your deck? and why?

Like there are so many but to me the best trump cards are the cards no one really tries using.. like for me my trump card is Road Warrior... many people dont really use this card much at all because of well because its hard to summon if your not using the right cards. like me i can bring it out in 1 turn..... plus it has a awesome affect which most people doesnt really look on because it can only special lvl 2 or lowers... so what are your trump cards in your deck? and why?