Welcome to the Ether Shop; at least the part where we get to dip our hands into all that dark magicky goodness. Yes, we do so enjoy this sort of thing here. Looking to create a Familiar demon for yourself or your Cubi, are you? You've come to the right place. We specialize in this sort of thing, you know. But you must wonder how a bunch of silly little stones and the like can create a Familiar? Let me read you a section from our Grimmoire of Familiar Formulas...

"We here at the Ether Shop have learned to create these Familiars through the means of black magic and alchemy combined! It's like raising the little buggers from hell... but in a mixing pot with a summoning spell instead!
As mentioned above, Familiars created through the Ether Shop are alchemy-made. This means that these creatures, though closely made to look like and mimic their actual spiritual counterparts in Hell, are unable to reproduce at all. So if you wanted to gift your Cubi a little demonling of their own for company and other mischief makings, you would need to come to us with the proper ingredients to create another one. Sorry, but a little bit of black magic can only provide so much."

Hopefully that has answered your curious little thought.