Gemini

Gemini was a virtual representation of one of Arno Dorian's genetic memories, relived by a Helix initiate through the Helix Navigator.

Description
Arno solved several riddles to find a part of the Nostradamus Disc.

First riddle
At the edge of the capital In the shadow of the wall The swamp of sorrows Burns the outcast's fire

Second riddle
Where the dead rest, Stone eyes watch. Vigilant guardians, In death as in life.

Third riddle
In the fetid muck Where the dark stream meets Her flowing mother You will find your goal At the foot of the old tower.

Outcome
Arno retrieved one of the fragments of the Nostradamus Disc.

Reference

 * Assassin's Creed: Unity