My main question is why do you need to summon anything, real or not, dealing with death? I know most people go through a phase where "darkness is cool" but despite how terrible a situation is death isn't the answer. Not unless you're being held against your will and being tortured in some way, even then I wouldn't summon something to kill another.
Research Azreal, find out what he favours and build and alter around that. Next cast a circle, give him an offering, and ask him to join you in the circle. He will not physically appear before you, but you should sense, hear, or feel him. This might take a few tries, so be patient and meditate quietly for a while.