In a civil lawsuit, the person who files the lawsuit is called the plaintiff, and the person being sued is called the defendant. Usually a plaintiff decides when, where, and whom she or he wants to sue. In some cases a plaintiff may wish to join, or add, other parties after the start of the lawsuit. .
1. Proper Parties: A proper party is anyone who is directly affected by the subject matter of the suit. he is joined because of the particular role he played which led to the cause of action
2. Desirable Parties: These are parties who are not originally parties to the action or whose presence are not so necessary for effective completion of the case but nevertheless, needs to be a party so that he will be bound by the decision in the case since the decision may directly affect him
3. Necessary Parties: As their name imply, they are needed and necessary for effective determination of the case and in whose absence, the proceeding cannot be fairly dealt with..
4. Nominal Parties: These type of parties do not have interest in the case but based on their office, should be joined to the case.
It is important to note that the Joinder, or addition, of a proper party in a pending lawsuit is entirely permissible. The court may allow the joinder of an additional party, but the lawsuit does not have to be dismissed if it does not.