Leo

Leo 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
Above the dark shadows Of the erstwhile bastion, The tall square Sentinel silently watches The 9th month spill his blood.

Second riddle
The martyrs of Herod, In their ageless temple, Haunt the alchemist's stones, With their macabre, soundless dance.

Third riddle
In the Belly of the World, The Saint of the Holy Stag Still waits for his Austral hand To reach the godly heavens.

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

Reference

 * Assassin's Creed: Unity