Nether Demon

I was told that Nether Demons were taken out of the game, which is sad but ok. The achievements are all still there, taunting me with their impossible to complete-ness. Any chance you can take away the achievements or put the nether demons back? There are a few achievements with them:

Name: Description. (Category)

Demonology: Transform a Nether Creature into a Nether Demon. (Creatures)
Walking the Demon: Use a Tome of the Demon on one of your creatures. (Items)
A New Identity: Use a Coin of Identity on one of your creatures. (Items)