Everything that is, was created by God. This does not mean that He “created” evil. He left room for evil by giving His creation free choice. He knew that evil would appear, but, He still allowed man to make the choice.

God is also a just God and everything that He does requires Him to act justly. Sin must be paid for, because it is injustice. Forgiveness is not “free” as some people tend to believe. Yes, God will forgive our sins but the price for sin must still be paid. God was willing to require the punishment (because He is just) and at the same time, pay the price for that penalty (that is why it is called grace, unmerited favor that you do not deserve, mercy, on the other hand, is not getting what you deserve). God is gracious with us as well as merciful. Yet, at the same time, He is just and demands payment/punishment for injustice. You can learn more about the character of God by studying the Names of God as revealed in the Bible.

No one is more powerful than God (study up on His Character and then take a look at human history, you will be amazed).

The lake of fire was also created by God as just punishment for Satan and His angels (read the story of what Satan attempted to do, along with 1/3 of the angels in heaven). It is a little more than just “unbelief”. God is just and He must require punishment for injustice. The lake of fire is the punishment (do not forget that man has been offered a 2nd chance and is valid as long as he is alive).

A just God requiring injustice to be punished cannot be immoral. It would be immoral if He did not punish injustice and just forgave unconditionally. All of God’s characteristics work together all at the same time (love, just, kind, merciful, gracious, all knowing, all powerful, etc.) You cannot divorce one aspect from the rest of them.