Who's unlocked joker?

I looked in the FAQ and it said D-Rank was what you needed but I went there with an E-rank monster with the stats of a C-Rank. I got pummeled mercilessly. I came back with a monster that'd cleared B-Rank and the fight was almost as hard.

I have unlocked the Joker, and he is very hard to beat. if you want my advice, you want high defence or speed, but you want one of those very high, and you want high skill, LP, and whatever you use to damage the opponent. and also, no matter what someone says, you can always train all the stats at once, it just will take a few times combining the monsters together. I made a Unique Anubis, and he had enough stats at the start to look at a Rank D and kill it.