Ozzy recorded two new studio tracks with Black Sabbath as part of the Reunion concerts in 1997; one of these was 'Psycho Man' which repeatedly includes the lyric 'he's the angel of death'. I think that'll be what you're talking about. It was on the live Reunion album 1998 as a bonus track along with 'Selling My Soul'.

Here's a link to Psycho man http://www.youtube.com/watch?v=yVBMRvJHzAQ

and Selling My Soul http://www.youtube.com/watch?v=9rbNZaVe1wY

Hope this helps you, peace!

--
You're my religion, you're my reason to live.
You are the heaven in my hell.
We've been together for a long long time,
And i just can't live without you.
No matter what you do, i'm here for you......