In Jain cosmology, we are currently in the era of the 24th Tirthankara, Mahavira, in the descending half-cycle (Avasarpini). After this half-cycle ends, the next half-cycle begins with the 1st Tirthankara again, which is Rishabhanatha (Adinath). So the “next era” would start with Rishabhanatha, followed by Ajitnath, Sambhavnath, and so on in the same sequence.