Who is the man shown in the last cutscene after beating Diablo?

I've just finished diablo 1 again, and something intrigued me.

After beating diablo, your hero remove the soulstone from his forehead (with a dagger), and after that he become human with a hole in the head.

Who is he ?

Image :

I have tried to find this on the internet but nothing...

If someone knows it would be cool :)

Link to the video

Solution 1:

It's Prince Albrech, son of King Leoric.

Unable to take King Leoric himself as a physical host, Diablo had the Archbishop Lazarus kidnap the king's son, Prince Albrecht, and brought him down into the Cathedral for Diablo to corrupt and use as his host to fully manifest as the Lord of Terror.

Source: Lore Summary