The Emerald Chain's chief scientist, who turned against Osyraa and helped the Discovery crew reach the source of the Burn.
Aurellio was a scientist who served Osyraa and the Emerald Chain. When the Chain captured Discovery and brought it to Federation headquarters, he interrogated Paul Stamets about the ship's spore drive, which he hoped to replicate for Osyraa.
He was horrified when Osyraa killed the Andorian Ryn, and after her death he had a change of heart. Aurellio suggested that Cleveland Booker's empathic abilities would let him navigate the spore drive in place of Stamets, allowing Discovery to jump into the Verubin Nebula to rescue its stranded away team.