I don’t think we can say that God truly sent the devil — also known as Lucifer, or later as Satan — down to earth in quite the way your question envisions. While the devil was cast out of God’s direct presence in heaven, this did not happen because God actively wanted Satan to have sway over his creatures.
Question Corner: Why did God send Lucifer down to earth?
New global initiative seeks to ‘unlock’ Catechism of the Catholic Church
Launched Sept. 7, the initiative includes videos, social media content and a podcast organized along the four pillars of the catechism.
Catechism will be updated to include ecological sins, pope says
Pope Francis said there are plans to include a definition of ecological and other “psycho-social phenomenon” hate sins in the Catechism of the Catholic Church.