Complex sentence: Sage was approached by his former professor, scientist Aristotle Rodor, who told Sage about an artificial skin he had co-developed with Dr. Twain called Pseudoderm.
Split into simpler sentences: Sage was approached by Aristotle Rodor, his former professor, currently a scientist. Rodor told Sage about an artificial skin he had co-developed with Dr. Twain called Pseudoderm.