I have only read the PHB of 5E, so I have no info about monsters.
Just to be sure: devils are still lawful evil and obsessed with contracts, usually to sell souls while demons are still chaotic evil and they inspire others to give into whatever negative emotions they have without caring about anything, so they enjoy lust, hatred, greed, violence and so on.
Prof. Dr. Dr. Mad S. Tist
World leading expert of artificial stupidity.
Because there are too many people who work on artificial intelligence already