Battle Coliseum was a 2v2 game that featured most of the characters from the SNK franchise. Some of them are The King Of Fighters, Fatal fury, Samurai Shodown… And according to this leak, we should expect a sequel.
The rumor is written in Japanese and can be seen here. When translated you can see that it mentions that the game will have cell shaded graphics like Gear Xrd. It mentiones that SNK will try to create a coherent story. In the sequel, a mysterious character is trying to gather powers from all the famous SNK characters throughout history and warriors from all times and locations will try to stop this unknown force.
Majority of the cast is also included in the leak.
Yuki – Ai (From the first Game)
Kyo Kusanagi – Iori Yagami (KOF series)
Terry Bogard – Rock Howard (Fatal fury)
Andy Bogard – Mai shiranui (Fatal fury)
Geese Howard – Wolfgang Krauser (Fatal fury)
Mr Karate 2 – Robert Garcia (Art Of Fighting)
Mr Big – John Crawley (Art Of Fighting)
Haohmaru – Kibagami Genjuro (Samurai shodown)
Nakoruru – Rimururu (Samurai shodown)
Kaede – Moriya Minaka (The Last Blade)
Marco rossi – Fio (Metal Slug)
Sho Hayate – Kim Sue (Kizuna Encounter)
Fuuma – Hanzo (world Heroes)
Ralf Jones – Clark Still (Ikari Warriors and KOF)
Athena Asamiya – Sie Kensou (Psycho soldiers and KOF)
Kusanagi Joe – Kisarah Westfield (Aggressors of Dark Kombat)
Bosses Include: Goodman – Mizuchi – Neo Dio among others
The leak also briefly mention that certain characters can transform mid battle. Examples were given for Iori turning into Orochi Iori, Nakroruru to Rera and Geese to his nightmare version.