I wrote this earlier (elsewhere ) for an Egyptian 'seeker ' ;
First, I am not Muslim nor Egyptian , so my cultural and spiritual understandings may be different to what you are used to . But I shall use your terms ;
The Qareen ( which may be more than singular ) , like many things ( humans, children , dogs , etc ) may be become wild and uncontrollable unless guided and nurtured properly . When this is done they can become loyal and helpful .
This is done by the power of and with the help of 'Al-Muhim' . This companion ( 'Angelic Qareen' ) can always over power and over rule the 'Djin Qareen ' .
In the Australian indigenous tradition , this is importantly connected to 'place ' , specifically birth place or 'home country' (area )
And here is a paper where a clinical psychiatrist discovered certain spiritual laws * could be used to treat people with ' multiple personalities ' ( or as some say , 'spirit possession ' ) ;
Many famous and inspired people throughout history have had such a companion and knew them by name . Also, at times , some people , who did not they had such a 'helper' would find them appearing in times of trouble and trials ;
I do not acknowledge any scriptural 'Devil' or Shaitan . Part of my studies include ancient Zoroastrianism, and I find there , that originally the concept of good and bad laid within 'mainyu' which became spirits ... but originally meant 'quality of mind' that is where 'evil' lies - not in nature , not in deity; we can have good or bad 'mind'
Our psyche needs to be trained and developed , to move toward good and to make the 'wild dogs' in the psyche , become 'good companions' that help and support the 'Al-Muhim ' .... otherwise one can become a man of conflict and disruption .
It does not matter how many unruly and untrained Djin Qareen try to assail one , if one knows the 'good companion ' .... the good companion ( as Dr. Wilson VanDusen - the psychiatrist in the above link - found out ) ;