Recently, I watched and finished Dexter: Original Sin (in about like 3 days! However it only had 10 50 minute episodes, so…) and it was really enjoyable for me!
I do really enjoy how it went in depth about how he slowly began down his path of becoming a serial killer and giving backstory on his family. There are flashbacks to how Laura (Dexter’s biological mother) and Harry (Dexter’s adoptive father) met, and those really gave me an insight on how Harry treated and adopted Dexter while growing him as a person and supporting his serial killer urges when he was younger, being around 2o in Dexter: Original Sin.
If anyone wants to get into Dexter it really helps to start here because it gives an insight into Dexter’s younger life before the original series while he was still starting out in forensics and becoming a serial killer.