Complex sentence: Ron Perlman serves as the narrator on every episode since the 3rd episode, except for the episodes'Tweets from the Dead' and'A New App Called Death', which featured Joe Irwin as a replacement narrator.
Split into simpler sentences: Ron Perlman serves as the narrator on every episode since the 3rd episode. Beginning with the episode'Tweets from the Dead', Joe Irwin is used as a replacement narrator.