By our practice, a counter-claim is clearly marked “COUNTER-CLAIM” and the defendant, who in his apparently changed status of plaintiff, avers in numbered paragraphs his claim which finally ends in the relief or reliefs sought. A counter-claim, though related to the principal action, is a separate and independent action and our adjectival law requires that it must be filed separately. The separate and independent nature of a counter-claim is borne out from the fact that it allows the defendant to maintain an action against the plaintiff as profitably as in a separate suit. It is a weapon of defence which enables the defendant/to enforce a claim against the plaintiff as effectually as an independent action. As a matter of law, a counter-claim is a cross action with its separate pleadings, judgment and costs. It is almost in a world of its own. But a counter-claim cannot be inconsistent with the plaintiff’s claim in the sense that it cannot erect a totally different case from that of the plaintiff.
– Niki Tobi JSC. Okonkwo v. Cooperative Bank (2003)