Ten Questions For God?

1. Why would God make a devil?

The Bible says He didn’t. He made a perfect super being (‘angel’)
who chose pride and selfishness and violence instead of love.
Ezekiel, a Bible prophet, wrote:

'The Lord spoke to me, saying, "Man, sing the saddest blues
for the King of Tyre [a symbol of Satan]. Tell him from Me:
'You had it all: perfection, wisdom, beauty! You were covered
in jewels and gems. I appointed you as the guarding angel.
You used to walk on God’s holy mountain, among the
sparkling stones. You were totally perfect when you were
made: until sin was found in you. You became greedy, and
war started in your heart. You sinned. So I threw you out of
the mountain of God like a nobody - and I will destroy you.
' " '
Ezekiel 28:11-17, paraphrased

Another passage gives the reason Satan lost it:

'How great is your fall from heaven, O shining one, son of the
morning! How are you cut down to the earth, low among the
dead bodies! For you said in your heart, I will go up to heaven,
I will make my seat higher than the stars of God; I will take
my place on the mountain of the meeting-place of the gods,
in the inmost parts of the north.  I will go higher than the
clouds; I will be like the Most High.But you will come down to
the underworld,even to its inmost parts.'

Isaiah 14:12-15 (Bible in Basic English)

Pride, selfishness, competitiveness. A summary of evil.