Marbas, alias Barbas is a great president, and appeareth in the forme of a mightie lion; but at the commandement of a conjuror commeth up in the likenes of a man, and answereth fullie as touching anie thing which is hidden or secret: he bringeth diseases, and cureth them, he promoteth wisedome, and the knowledge of mechanicall arts, or handicrafts; he changeth men into other shapes, and under his presidencie or gouvernement are thirtie six legions of divels conteined.
Johann Weyer, Pseudomonarchia Daemonum
Marbas rules over 36 legions of Spirits. He can reveal hidden secrets to you. Also Marbas causes diseases and cures them (Marbas can be called upon for cursings). He gives knowledge in mechanical arts.
Goetia & Daemonolatry Goetia by S. Connolly
When to summon Marbas?
Summon Marbas during Wednesdays and when the moon is waxing, full or waning.
You can fine tune your spells by doing it during the astrological hour of Mercury.
I have also made a video about healing spells with Heramael and Marbas (for pets), but the method shown in the video is suitable for healing adults and kids too.
By the way, my little Cackatoo has grown out his feathers and all the feather plucking has stopped long ago.
But he is a little phobic bird and he is even afraid of the lamp in the ceiling, because he thinks the lamp is a predator bird.
So, now demon Ipos is healing the phobic fears in my little cackatoo and the spells already show good results.