Demon Focalor is a great duke comming foorth as a man, with wings like a griphen, he killeth men, and drowneth them in the waters, and overturneth ships of warre, commanding and ruling both winds and seas.
And let the conjuror note, that if he bid him hurt no man, he willinglie consenteth thereto: he hopeth after 1000 yeares to returne to the seventh throne, but he is deceived, he hath three legions.
Johann Weyer, Pseudomonarchia Daemonum
Demon Focalor rules 30 legions of Spirits and his duty is to slay people. Summon Focalor for curses, because he will help you to defeat your enemy.
Source: Goetia & Daemonolatry Goetia by S. Connolly
How to summon Focalor?
I have made a video about Focalor as a way to thank him for protecting me. I also believe that baneful magick with Focalor could go very wrong if we overdo our intent.
I have been shown in a dream what Focalor is capable of: he can kill people in accidents by overthrowing cars and trucks.
That dream Focalor sent to me was a nasty one and I woke up in terror.
When to summon Focalor?
Use the correspondences of Netzach even for Harab-Serapel:
Ruling planet: Venus
Astro hour: Venus
Paper seal colour: green
Metal seal: copper
Herb: cinnamon (my own choice)
The best day to summon Focalor is a Friday as near to the full moon as possible.
If your target is a very dangerous person, I suggest to create his doll. Why his?
Well, women are not dangerous physically, because most of them come to sprinkle grave dirt on your porch. That is all.
But some men are really dangerous in a physical sense.
You can do a binding spell with Focalor and ask Focalor to physically eliminate the person if they attempt to come to your place without your consent (of course they plan to come with malicious intent).
Such magick is ethical, because you are protecting your life.