Lucifer,morning star, The Lord of Evil and Decieve, and lies.
Lucifer
there is no such thing as powerful anything except what god gave them
Yes he is. Sesshomaru is a very powerful demon. he even surpassed his father who is said to be one of the most powerful demon in the Inuyasha world. and it is said that when it comes to raw power no one can beat Sesshomaru.
There's no definite answer, but it's probably Lilith. Lilith was the first demon created by Lucifer and is considered the mother of all other demons.
The name "Lord of the Flies" is a literal translation of the name of the biblical name Beelzebub, a powerful demon in hell sometimes thought to be the devil himself.
I don't know about Demon Child. But the name Raksha means Demon.
The most powerful demon is the one who can cause suffering to both humans and ghosts. He/she takes many forms and names through out different religions and culture.
'Beelzebub has a devil put aside for me...' Queen, Bohemian Rhapsody
He controls a Jinchuuriki, the one tailed demon.
Demon Dan's birth name is Daniel Blackner.
Summoning a demon requires correct and complete knowledge of the "true" name of the demon you intend to summon.
One demon is often refered to as 'Satan'.