Paul was pretty evil killing and arresting Christians, but God's mercy turned him into the greatest apostle of all times.Jesus says "No one is Good but God alone". That means if God kills someone, it's because He's Holy and they are evil and deserve it, which is God's Justice, a part of God's Goodness. It also means that if God saves someone, it is because He is Merciful, which is also part of His Goodness. If God does it, it's Good because He is Good, whether He kills or heals, whether He saves or destroys. God is good to create Lucifer, let Satan live and blaspheme and kill and destroy, and then finally destroy him forever in the Lake of Fire. This is God's Goodness. God is also Good to come in the flesh of Jesus Christ, take our sins, die a horrible death, and then raise Him from the dead, honoring Him forever in Heaven. This is also the Goodness of God.
The Bible records drunks, prostitutes and homosexuals turning from deadly sin to God.
God putting Lucifer and the like a fire for eternity is justice.
The lake of fire destroys no one. Everyone, saved and unsaved, exist forever.
Justice is good.