Complex sentence: He is the owner and co-founder of the fictional Umbrella Corporation, and is often mentioned within documents in the "Resident Evil" series; however, he has never made a physical appearance in any of the series' installments.
Split into simpler sentences: He is the owner and co-founder of the fictional Umbrella Corporation, and is often mentioned within documents in the "Resident Evil" series. However, he has never made a physical appearance in any of the series' installments.