How about Geth's Verdict instead of Hideous end? It costs less and even can kill anything but does everything else the same. Also How about take out 2 Duress for 2 Hymn to Tourach? This gives you some late game flexibility because the discarded cards are 1. random and 2. they could be anything. Also if you would like any ideas for removal/ramp/mono-black stuff look at my budget-ish mono-black ramp, yeah thats a thing, deck. Hardcast Emrakul, or Exsanguinate for 35? You pick

Thanks for your suggestions Coinman1863!
I agree with your opinion on Hymn to Tourach, I'll try to get a couple of them to my deck.
In this deck, I prefer using Hideous End over Geth's Verdict because I made some tests with this deck and I noticed that I didn't have any pin-point removal. Go for the Throat would be much better, but is a little expensive to get 3 of them. Doom Blade would also be cheaper to play, but I use it in another deck, so I decided to vary the cards that I use and Hideous End seemed nice to me.
I'll also check on your deck and see if there's good cards that would combine well in this deck ;)