There are several rules under the Kenya civil procedure rules of 2010 in regard to parties to a suit.
Rule 1- Who may be joined as plaintiffs- All persons may under Kenya laws be joined in one suit as plaintiffs in whom any right to relief in respect of or arising out of the same act or transaction or series of acts or transactions is alleged to exist, whether jointly, severally or in the alternative, where, if such persons brought separate suits, any common question of law or fact would arise.
Rule 2- Power of court to order separate trial- Where it appears to the court that any joinder of plaintiffs may embarrass or delay the trial of the suit,
the court may either on the application of any party or of its own motion put the plaintiffs to their election or order separate trials or make such other order as may be expedient.
Rule 3- Who may be joined as defendants- All persons may under the Kenya laws be joined as defendants against whom any right to relief in respect of or arising out of the same act or transaction or series of acts or transactions is alleged to exist, whether jointly, severally or in the alternative, where, if separate suits were brought against such persons any common question of law or fact would arise.
Rule 4- Court may give judgment for or against one or more of joint parties- Judgment may be given without amendment—
(a) for such one or more of the plaintiffs as may be found to be entitled to relief for such relief as he or they may be entitled to;
(b) against such one or more of the defendants as may be found to be liable according to their respective liabilities.
Rule 5-Defendant need not be interested in all relief claimed- It shall not be necessary that every defendant shall be interested as to all the relief claimed in any suit against him.
Rule 6- Joinder of parties liable on same contract- The plaintiff may at his option join as parties to the same suit all or any of the persons severally, or jointly and severally liable, on any one contract,including parties to bills of exchange and promissory notes.
Rule 7- When plaintiff in doubt from whom redress to be sought- Where the plaintiff is in doubt as to the persons from whom he is entitled to obtain redress, he may join two or more defendants in order that the questi on as to which of the defendants is liable, and to what extent, may be determined as between all parties.
Rule 8- One person may sue or defend on behalf of all in same interest- Where numerous persons have the same interest in any proceedings, the proceeding may be commenced, and unless the Court otherwise orders, continued, by or against anyone or more of them as of all in same representing all or as representing all except one ormore of them.The parties shall in such case give notice of the suit to all such persons either by personal service or, where from the number of persons or any other cause such service is not reasonably practicable, by public advertisement, as the court in each case may direct
Rule 9- Misjoinder and non-joinder- No suit shall be defeated by reason of the misjoinder or non-joinder of parties, and the court may in every suit deal with the matter in controversy so far as regards the rights and interests of the parties actually before it.
Rule 10- Substitution and addition of parties- Where a suit under Kenya law has been instituted in the name of the wrong persons as plaintiff, or where it is doubtful whether it has been instituted in the name of the right plaintiff, the court may at any stage of the suit, if satisfied that the suit has been instituted through abona fide mistake, and that it is necessary for the determination ofthe real matter in dispute to do so, order any other person to be substituted or added as plaintiff upon such terms as the court thinks fit.The court may at any stage of the proceedings, either upon or without the application of either party, and on such terms as may appear to the court to be just, order that the name of any party improperly joined, whether as plaintiff or defendant, be struck out, and that the name of any person who ought to have been joined, whether as plaintiff or defendant, or whose presence before the court may be necessary in order to enable the court effectually and completely to adjudicate upon and settle all questions involved in the suit, be added.No person shall be added as a plaintiff suing without a next friend or as the next friend of a plaintiff under any disability without his consent in writing thereto.Where a defendant is added or substituted, the plaint shall, unless the court otherwise directs, be amended in such manner as may be necessary, and amended copies of the summons and of the plaint shall be served on the new defendant and, if the court thinks fit, on the original defendants.
Rule 11- Conduct of suit- The court may give the conduct of the suit to such person as it deems proper.
Rule 12- Appearance of one of several plaintiffs or defendants for others- Where there are more plaintiffs than one, any one or more of them may be authorized by any other of them to appear, plead or act for such other in any proceeding, and in like manner, where there are more defendants than one or more of them may be authorized by any other of them to appear, plead or act for such other in any proceeding.The authority shall be in writing signed by the party giving it and shall be filed in the case.
Rule 13-Practice- Any application to add or strike out or substitute a plaintiff or defendant may be made to the court at any time before trial by chamber summons or at the trial of the suit in a summary manner.
Rule 14- Notice to third and subsequent parties- Where a defendant claims as against any other person not already a party to thesuit (hereinafter called the third party) —
(a) that he is entitled to contribution or indemnity; or
(b) that he is entitled to anyrelief or remedy relating to or connected with the original subject-matter of the suit and substantially the same as some relief or remedy claimed bythe plaintiff;
(c) that any question or issue relating to or connected with the said subject-matter is substantially the same question or issue arising between the plaintiff and the defendant and should properly be determined not only as between the plaintiff and the defendant but as between the plaintiff and defendant and the third party or between any or either ofthem,he shall apply to the Court within fourteen days after the close ofpleadings for leave of the Court to issue a notice (hereinafter called a third partynotice) to that effect, and suchleave shall be applied for by summons in chamber ex parte supported by affidavit. A copy of such notice shall be filed and shall be served on the third party according to the rules relating to the service of a summons.The notice shall state the nature and grounds of the claim, and shall, unless otherwise ordered by the court, be filed w ithin fourteen days of service.
Rule 15- Default of appearance by third party- If a person not a party to the suit desires to dispute the plaintiff’s claim in the suit as against the defendanton whose behalf the notice has been given, or his own liability to the defendant, the third party must enter an appearance in the suit on or before the day specified in the notice; and in default of his so doing he shall be deemed to admit the validity of the decree obtained against such defendant, whether obtained by consent or otherwise, and his own liability to contribute or indemnify, as the case may be, to the extent claimed in the third-party notice: Provided that a person so served and failing to enter an appearance within the period fixed in the notice may apply to the Court fo r leave to enter an appearance, and for good cause such leave may be given upon such terms,if any, as the court shall think fit.
Rule 16- Where a third party makes default in entering an appearance in the suit, or in delivering any pleading, and the defendant giving the notice suffers judgment by default, such defendant shall be entitled, after causing the satisfaction of the decree against himself to be entered upon the record, to judgment against the third party to the extent claimed in the third-party notice; the court may upon the application of the defendant pass such judgment against the third party before such defendant has satisfied the decree passed against him:Provided that it shall be lawful for the court to set aside or vary any judgment passed under this rule upon such terms as may seem just.
Rule 16- No judgment against Government without leave of the Court- A defendant shall not in any event be entitled to enter judgment against the Government under rule 19 without the leave of the court. Any application for leave to enter judgment against the Government shall be made by chamber summons served not less than seven days before the return day.
Rule 17- Judgment after trial against third party in default-Where a third party makes default in
entering an appearance in the suit, and thesuit is tried and results in favourof the plaintiff, the court may either at or after the trial enter such judgment as the nature of the suit may require for the defendant giving notice against the third party:Provided that execution thereof shall not be issued without leave of the court, until after satisfaction by such defendant of the decree against him.
If the suit is finally decided in the plaintiff’s favour, otherwise than by trial, the courtmay, upon application ex parte supported by affidavit, order such judgment as the natureof the case may require to be entered for the defendant giving the notice against the third party at any time after satisfaction by the defendant of the decree obtained by the plaintiff against him.
Rule 17- Appearance of third party and directions- If a third party under Kenya laws enters an appearance pursuant to the third-party notice, the defendant giving the notice may apply to the court by su mmons in chambers for directions, and the court upon the hearing of such application may, if satisfied that there is a proper question to be tried as to the liability of the third party, order the question of such liability as between the third party and the defendant giving the notice, to be tried in such manner, at or after the trial of the suit, as the court may direct; and, if not so satisfied, may order such judgment as the nature of the case ma y require to be entered in favour of the defendant giving the notice against the third party.
Rule 18- The court may decide all questions of costs between a third party and the other parties to the suit, and may make such orders as to costs as the justice of the case may require.
Rule 19- Defendant claiming against a co-defendant- Where a defendant under Kenya law desires to claim against another person who is already a party to the suit—
(a) that he is entitled to contribution or indemnity; or defendant.
(b) that he is entitled to any relief or remedy relating to or connected with the original subject-matter of the action which is substantially the same as some relief or remedy claimed by the plaintiff; or
(c) that any question or issue relating to or connected with the said subject-matter is substantially the same as some question or issue arising between the plaintiff and the defendant and should properly be determined not only as between the plaintiff and the defendant but as between the plaintiff and the defendant and such other person or between any or either of them,the defendant may without leave issue and serve on such other person a notice making such claim or specifying such question or issue.