Help beating Phoenix

At your level there is no specific character to kill first. The correct answer is to check each character out first and go for the weakest, which is usually Hera or Chopper. Every character you knock off gimps the team and Hera is a good target due to her ability to backup plan and waste all your efforts. I find myself having to phoenix vs phoenix a lot on my new shard and that's what I've been doing. I also keep track of who I beat for later.