Using this: http://eeemo.net/

For demonic speech. Demonic speech itself will lack certain words, considering that it's a horrible language used for dominion and destruction. Well, it's possible to express some feelings, but it'll be quite roundabout. Like 'peace' will mean:

"A̶ ͘t͟ime ǫf̧ ͝lack͠ of war ͡whe̸r͡e͜ it͏ ͘is ̶bene͞fic̢iál̕ f́o̧r̀ b͡o͟t̶h ̡gr͝o̸ups.̶"