Deuteragonist

In literature, the deuteragonist (/ˌdjuːtəˈræɡənɪst/ DEW-tə-RAG-ə-nist; from Ancient Greek δευτεραγωνιστής (deuteragōnistḗs) 'second actor') or secondary main character is the second most important character of a narrative, after the protagonist and before the tritagonist. The deuteragonist often acts as a constant companion to the protagonist or as someone who continues actively aiding a protagonist. The deuteragonist may switch between supporting and opposing the protagonist, depending on their own conflict or plot.