The members of the Lost Souls are Dirge (leader), Requiem, Lament, and Desolation. They have the ability to absorb other's psyches by trapping them within a particular emotion relevant to the victim. When they attacked the X-Men, they absorbed Remy, Beast, Storm and Jean Grey (Dirge attacked Remy by trapping him with his guilt; Requiem attacked Beast by trapping him with his hatred; Lament attacked Storm by trapping her with her rage; Desolation attacked Jean by trapping her with her vengeance.), but only for a time, and were eventually defeated.
The Lost Souls were created by Chris Claremont and Tom Raney in 2000 and first appeared in The Uncanny X-Men # 382.