The "Making of" documentary was split into two parts:
* Relentless: The Making of Elektra – Part 1: Production (87:14)
* Relentless: The Making of Elektra – Part 2: Post‑Production (53:09)

The Blu-ray/DVD also has *Elektra: Incarnations* (52:46) documentary which goes in detail about the comic origins of the character.
Fun fact: The longest "Making of" documentary made for a Marvel film is for Elektra (2005) clocking in at 2 hours 20 minutes.