Re: Mt battle?
Well You can read it in your instruction booklet but to save you the trouble I'll type the passage from the book.
In this Colosseum battle, your goal is to beat eight trainers in a row. The Pokémon's level restrictions and strength of the opponents differs depending on the Colosseum.
My only guess is that you have to bea all eight trainers of each mode in both single and double battle to unlock the 2 ????? colosseums and beat all 8 trainers in both double and single battle on them. Then that's when you will get Entei. That might not be but it's the most resonable answer I can come up with. You might just need to beat all modes in each type of battle a certain amount of times until you finally win Entei. Somebody else may have already done this though so if they did they can tell you.
((I just want Suicune though so if that's true you prolly won't find out if it is from me. I might beat it if I have nothing else to do though.))