I remember seeing first 2 episodes. Its about a group of children, I think 12, they were away from home at some place near the beach. the kids find a cave near the beach and there they see a machine which was built by this crazy dude asking them if they want to play a game. The kids agree and suddenly this robot? appears and the twelve children are inside this thing. Inside the robot? there are twelve chairs for each children and when this robot? appears, an enemy comes out and they must destroy it. One kid becomes the leader but every leader dies after successfully defeating the enemy?
Sorry for the vague description, I don't really remember this anime but it was really interesting and want to finish it. Thanks for looknig.













