There shall be a complaint, petition, application or written request, as required by statute, and an answer that may include a counterclaim and/or cross-claim(s); a reply to a counterclaim denominated as such; an answer to a cross-claim, if the answer contains a cross-claim; a third-party complaint, if a person who was not an original party is summoned under the provisions of Rule 14 of these rules; and a third-party answer, if a third-party complaint is served. No other initial pleading shall be allowed, except that the court may order a reply to an answer or a third-party answer.