DIANE D The Return Of The Other Personality – Volume 4 involves Diane D being let out of the mental institution temporarily on house arrest and is in her family's custody for the time being and is back at the organization. It is causing fear around the organization, making everyone feel very uncomfortable and very afraid knowing that Diane D's presence is there at the organization. Several children at the organization frighteningly approach the staff members and claim to have seen Diane D sitting in a chair inside her grandmother Margarita's office angrily looking out the doorway at them as they passed by Margarita's office doorway. Staff members start to wonder could it be the evil, vicious, powerful, dangerous and murderous other personality of Diane D's sitting there in the chair inside Margarita's office angrily looking out into the hallway at the children. The children also claim to have seen something black strapped around both of Diane D's ankles. Michael's parents are soon worried for his safety being married to Diane D. They try to convince him to leave Diane D.
A producer puts Diane D and Dana in an online sword fighting commercial. Controversy arises over Diane D and Dana's online sword fighting commercial. Kurt whose father was one of the authority figures killed by Diane D's other personality, claim that since Diane D and Dana are murderers, they do not need to be making any profits from anything! The producer caves in and cancels the online sword fighting commercial, causing Diane D and Dana not to make any profits from it! Kurt then claims to see Diane D stalking him in different places! Diane D denies ever stalking Kurt. Kurt then gets nightmares about Diane D stalking him inside some creepy woods at night while she is walking bent all the way backwards on all fours handcuffed, shackled and chained trapped in a contortionist position! In another nightmare, Kurt is stalked by Diane D again! This time, he is stalked, chased and attacked by multiple females in the woods who look and dress exactly like Diane D, around ten to fifteen of them! Kurt becomes shocked seeing multiple beings who look and dress exactly like Diane D! He realizes that his soul or spirit is in some type of spiritual underworld. He then realizes that these beings who look and dress exactly like Diane D are not human, but actually demons! He realizes that he is trapped in the spiritual underworld with these demons who look exactly like Diane D! The demons then tie Kurt up! They light up his fingers as they are about to set him on fire! They then turn and hurry away from Kurt! They run far from him and form a line facing him! They then give Kurt a death stare as they stand there ready to watch him burn alive! Kurt then wakes up screaming! He is out of breath as he frighteningly looks around the room. He does not see the demons who look exactly like Diane D anymore. He is saved from them simply by waking up! He later tells his family about his horrific nightmares about the multiple demons who look exactly like Diane D that try to set him on fire and watch him burn alive!

One day, Diane D makes an apologetic speech to the victims' family members inside a hotel conference room. Later on, tensions start to flare as the widows and Diane D go at each other! Jeremy whose father was also killed by Diane D's other personality hollers and yells at Diane D! He starts to head right towards her! He approaches Diane D at the front of the room and tries to attack her. Diane D gets on the defense as she and Jeremy get into a physical altercation! She overpowers Jeremy putting him into a chokehold! She then becomes a one-woman army and causes countless members of the victims' families to be...