List and explain the six types /roles of people directly or indirectly involved in bullying

There is the bully. These people may be bullying the person right in front of them or behind their backs. They are the main abuser.
There is the one who is being bullied. These people are being picked on and abused. They do not fight back, if someone does fight back it's not necessarily bullying. They are the main victim.
There is the assister. These people don't start the bullying but they also bully the victim. They could encourage it or join it.
There are the reinforcements. They don't directly get involved with bullying, but are like an audience. They support the bully and cheer them on.
There are the outsiders. They stay away from the situation and do not defend the victim or support the bully. 
There are the defenders. They come to the victim's defense and speak up for them, comfort them. They support the one who is being abused.

Kids who bully - these are children who engage in bullying behavior towards their peers.

Kids who are bullied - these are the children that are the targets of the bullying behavior.

Kids who assist - these children may not start the bullying or lead the bullying behavior, but serve as an assistant to other children who bully.

Kids who reinforce - these are children not directly involved in the bullying behavior but they give the bullying an audience.

Outsiders - these children remain spectate from the bullying situations.

Kids who defend - children who actively comfort the child being bullied and may come to the child’s defense when bullying occurs.