Demon Form

Demon form does not work with Grim Feast even at 170 spirit.

Blasphemy seems to turn off in demon form in certain situations, or flat out doesn't let me enter demon form when it's enabled... but I can confirm that I have enough spirit available for it (I can see the reduced spirit balance above my mana while in demon form).

But get this - If you go into your skills while you're IN demon form, I can right click Blasphemy and turn it back on! Something is definitely bugged here...

I have discovered a solution for this. Sadly aura gems in the demon skill dont work. But you can make them work if you have something like withering presence or grim feast. You need to activate them in the second weapon slot and then it work, dont ask me why the first slot dont work and the shapeshift slot also dont work.

Ain't got the energy to read that much. Replying to all.
SOcket gems into the second set. Don't care about the bugged shapeshift set.
There's no issue whatsover with spirit. U lose weapon stats. Using set skills without the needed spirit will nderstandably turn the demon form off

If you are on mouse and keyboard you can hit the arrow next to the gem and apply the aura to the demon form. You cannot do this on controller and it will turn off if you switch back to controller.