Mercurius

Mercurius 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
The lady of the domicile Judges comings and goings From her couch-like throne At the top of the stair.

Second riddle
Lowly sinners, as each we are, Apsire to the domed heav'ns. Fickle fate points beyond, Where a supine city Beckons.

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

Reference

 * Assassin's Creed: Unity