Complex sentence: Not much is known about Simkin's age, he could be 100 years old or as old as time itself, Simkin however can look anything from 14 to 75 years old.
Split into simpler sentences: Not much is known about Simkin's age, he could be 100 years old or as old as time itself. Simkin, however, can look anything from 14 to 75 years old.