Complex sentence: As a former angel of Heaven, Zauriel is essentially immortal, immune to usual mortal frailties such as aging and disease, apparently not needing food, water, air or sleep, and having endured for millions of years serving Paradise.
Split into simpler sentences: As a former angel of Heaven, Zauriel is essentially immortal, immune to the usual mortal frailties of aging and disease. He apparently does not need food, water, air or sleep, and has endured for millions of years serving Paradise.