Apostasy Prologue

Apostasy Prologue is a short main Quest released in, not found in the Codex until completion. This quest relives Margulis' final moments with Ballas before her execution and the latter's meeting with the Lotus.

Walkthrough
''WARNING: The walkthrough ahead contains significant spoilers to Warframe's lore. It is recommended to play through the quest first.''

In order to access this quest, the player must have first completed the Chains of Harrow quest, as well as have access to their Orbiter's Personal Quarters.

The Orbiter: Personal Quarters
In the Personal Quarters, a holographic, violet Lua orb can be seen floating at the end of the room near the port window. Approaching the orb and touching it will transition the Tenno into the loading screen.

The Reservoir
After loading in, the player will find themselves on Lua to find yet another orb. This time, approaching the orb will reveal a purple trail that will lead the player through the map. While following the trail the player will hear past dialogue between Margulis and Ballas, from before Margulis' execution.

At the end of the trail is a broken Reservoir. The trail will lead down a pit where the player will jump down and be forced to enter Operator mode.

The Jade Light
There, the player will hear echoes of the last few moments leading up to Margulis' execution and find a pod at the end of the hall, where a cutscene will play.

As the pod opens the Lotus is revealed inside, with wires connecting to the back of her head. The Lotus extends a greeting, and before the Operator can reply, Ballas himself replies to it. He then steps forward and apologizes to the Lotus for being gone for so long. The Lotus tries to explain that she is not Margulis, but Ballas insists and waves out his hand. A wave of energy flows out (which also slightly distorts the player's screen similar to the Somatic disruption during The Second Dream) and the Lotus is detached from the pod.

She then removes her mask as Ballas promises not to abandon "Margulis" again, and takes his hand. Both Ballas and the Lotus walk into a blinding light away from the Operator. Attempting to follow Ballas, the Operator is knocked back by an energy shockwave instead.

After the Lotus and Ballas disappear the Operator clutches the Lotus' dropped helmet, looking around confused at now being alone.

Epilogue
Back at the Orbiter, Ordis states that he will search for the Lotus' current whereabouts and in the meantime attempt to synthesize the Lotus' mission directives.

Trivia

 * Apostasy refers to the abandonment of a belief or religion.
 * The blinding light into which Ballas and the Lotus disappear mirrors the execution of an Archimedian heavily implied to be Margulis, as expressed in the Detron Crewman's Synthesis imprint.

"They opened the chamber door just in time for me to see it happen; the Archimedian erupting into a flash, jade-like and blinding. I knew her. She was the greatest scholar of genetics who ever lived. Except now she was nothing but mist and gore."

- Archimedian Perintol


 * The motion of which Ballas waves his hand to disengage Lotus mirrors that of the handwave used by an Orokin Executor named Avantus to access a (presumably Orokin) console as expressed in the Arid Eviscerator's Synthesis imprint.

"We paced in silence until one of the Grineer, that big one, ran to a tool case on the wall and tried to force it open.

Avantus noticed this and waved her hands over the nearby console to unlock the case."

- Bilsa

Bugs

 * The glowing orb in the Personal Quarters may not appear immediately upon completing the Chains of Harrow quest. Logging out of the game and then logging back in or simply leaving and re-entering the Orbiter after completing the quest can solve this issue.
 * The final audio when walking through the hallway leading to Lotus may not play.