for Kaiba to not attack Vassal when you have only 1 card left in your deck is he must have more cards then you so if u have 1 card left in your deck he must have 2 and you must also set your backrow if not he will attack Vassal
If you only have D.Gate and facedown field spell on the field, he will attack your vassal. You should clog your field by setting your Union attack or secret pass to make sure Kaiba won't attack your vassal..
Anonymous
Nubashet
