Crossbow Minion tells you, "Yes, I still obey the Master. If you have the Glowing Virindi Cloak, I will take it in exchange for the Singularity Crossbow. Please. If you have a Singularity Crossbow, let me enhance it for you. Please?"
You give Crossbow Minion Glowing Mosswart Shroud.
Atlatl Minion gives you Singularity Crossbow.