Cassian is Amadei Derros's associate and assistant in his agenda.
At some point, Cassian started assisting Amadei in his objective to physically and spiritually heal not only aliens, but also humans. They then lived together in the same house. This house would then become a place where aliens who wanted to be healed came to Amadei and were healed.
Cassian then accommodated Kara Danvers and Nia Nal when they entered their home, who interviewed Amadei. Later that night, he went to give Amadei his tea, as he always does, and went to his room to sleep. When he went to wake up Amadei in his room, he was shocked to see that the amulet attached to Amadei's chest was gone, and went to Al's Dive Bar to ask help from J'onn J'onzz, who also called Kara to help. They then proceeded to their house and told them of what happened and Amadei's condition. Kara suggested that they call the police, to which Cassian declined, as Amadei's community doesn't trust them and that there was still too much prejudice against aliens. Cassian then asked J'onn for help in investigating the crime, and let him read his mind. They saw an unfamiliar woman, which led them to believe that she might be one who stole Amadei's amulet. This woman was later revealed as Elizabeth Hawkings, Amadei's daughter.
Later, Cassian called J'onn about the ongoing vigil outside for Amadei where his devotees prayed for him.
When the D.E.O. retrieved the amulet from former agent Raymond Jensen, Cassian then watched as J'onn placed Amadei's amulet back to his chest and he regained his health, also witnessing Amadei and his daughter Elizabeth reconnect with one another.