Actually, that's Team 8, not 5. It's in the Grand Magic Games rules that there must always be an even amount of teams. For example, when Raventail got disqualified for cheating, Fairy Tail Team A and Team B were told that they must mingle and become one team. The reason for that was so each team could be in the battle part of the games. 
Also, there were eight teams in the series, so I just decided to have an eighth team. If we wanted, we could always have it an existing team such as Blue Pegasus or something.

What spirit was Books working on? I thought she made Tua