I'm only around episode 280 (Naruto and Bee are on their way to join the war), so I haven't seen too much of the tailed beasts, so, with that disclaimer, based on my limited knowledge, I'm going with the 8-tails. I love his kind of more serious, reserved attitude juxtaposed with Killer Bee's eccentricities, and the way they work together! I'm sure he was probably more angry and unstable before Bee learned to control him (though it seems to me that it came pretty naturally to him), but he seems really cool and wise, even taking the wheel sometimes in training to provide guidance to Naruto. Since I still have a lot to learn about the Bijuu, that's all I have for now!
Until next time! Here are my other cards for this Naruto Giveaway, if you wanna check 'em out:
Day 1: Most Awesome Character
Day 1 prompt card: Most awesome character
Day 2 prompt card: Favorite Tailed Beast