Xavier Castillo is a minor character on How to Get Away with Murder. He is the brother to Laurel Castillo and was the person responsible with organising the murder of Nathaniel Lahey, Sr. to get back at Annalise for sending his father to jail, subsequently ruining his family.
- Nathaniel Lahey, Sr.: Though it was initially believed to be Lynne Birkhead who made the order, Xavier supposedly gave the order to C.O.s Paula Gladden and Jim Wagner to assassinate Nate and make it look like it was a justified kill. During transport to a psychiatric facility, Nate was shot in the head. However, the official story is that Nate attacked Paula when she tried to take his letter off of him before transport. Nate became agitated and stabbed Paula in the leg with a pencil which forced C.O. Wagner to shoot Nate in the head. The death was ruled a justifiable death. ("We Can Find Him", "I Got Played", "Make Me the Enemy")
- It is unknown whether Xavier is meant to be Adrian Castillo, just renamed, as the Castillo's have never mentioned another brother, nor has he been mentioned by name since "Best Christmas Ever".
|"Your Funeral"||"Whose Blood Is That?"||"The Baby Was Never Dead"||"It's Her Kid"||"It Was the Worst Day of My Life"|
|"We Can Find Him"||"I Got Played"||"I Want to Love You Until the Day I Die"||"He Betrayed Us Both"||"Don't Go Dark on Me"|
|"Be the Martyr"||"We Know Everything"||"Where Are Your Parents?"||"Make Me the Enemy"||"Please Say No One Else Is Dead"|