Grey stone

[Superba]

Heart Protus gave me the Grey stone, but there is no such thing in my inventory, is this normal?

[Ouroboros]

Are you talking about stone that he gave you for opening those gates in Black Fortress? If yes then yes it is normal.

[Lilith]

If you mean the thing he wants you to use at the end of the game, it appears in your special items list (accessed from the same screen as your journal and quest list), not your regular inventory. It'll activate automatically when needed.

[Superba]

Thanks! Yes I refer to socalled Grey Stone, this is the name in game of the item. I am relieved now because in the Corruption after Miranda's fight the talking construct volunteered to give me a prize, a something that whatever it was I couldn't find in my pockets, so I started to worry there was something wrong with the Grey stone too. By the way, what is the "compensation" the construct gave/gave not to me?

[Lilith]

Thanks! Yes I refer to socalled Grey Stone, this is the name in game of the item. I am relieved now because in the Corruption after Miranda's fight the talking construct volunteered to give me a prize, a something that whatever it was I couldn't find in my pockets, so I started to worry there was something wrong with the Grey stone too. By the way, what is the "compensation" the construct gave/gave not to me?

 

As it told you, the reward for your help was that it gave you a chance to run away before trying to kill you. That's all. No more, no less.