Re: how many monsters???

Besides 1v1, 3v3, and 6v6, there's also 10v10, 15v15, 21v21, and 28v28. Those are the official levels of combat, but I figure if you're really bored/crazy and you have the cards, you could keep on going (36v36, 45v45, etc). You would have to do this in a real-world game, because I don't think the online version goes past 28 creature armies.