C Common Doble Passe X TRAP When an opponent's monster declares an attack on a face-up Attack Position monster you control: Make your opponent's attack a direct attack instead and inflict damage to your opponent equal to the ATK of the attack target you control
Callous BloodmageCallous Bloodmage can do the same, but can also create a blocker or exile a problematic graveyard
Its simple to use and can disarm any Lost Zone strategy you can imagine!
One of the most powerful Link monsters ever printed is currently banned, as its generic negation was too frustrating to deal with in the meta
Once this card has been discarded, you could potentially use it for synchro summoning: its a level 3, which is a great level for all sorts of summons, and its kept safe in your graveyard for you to summon whenever you like.
Superficially, that's a great gameplay match for how Aang enters the story