Good story/manga title plz? :D?

[IsabellaJiang]

I'm writing-drawing a new manga and I wanted a good name for it but my mind went blank. Um, the story is about a group of people who start off as two girls who recruit others into positions into their teams. Um, the two girls at the beginning are siblings, and they are two of the strongest 'fighters' in this story. There are many other people, and the story evolves around them going to a tournament and changing and growing during the course of it. The tournament is very dangerous, and it is one were you fight for your life and prizes, they are always in danger. Um... Some people have 'powers' like the elements and all sorts of stuff.(clichéd but I like it). If possible, could the title include the word 'black' in it? And also the japanese name in romaji plz. Ty