While I like the idea, im not sure about your commander. I really like him in Kaalia decks, since you can avoid paying the attack cost.
The Problem in your deck is, a boardwipe or even a
Fog in the right moment and you're really f*cked up because "Non-Demon Permanent" includes your lands. So you usually have to be very sure that Rakdos will hit the Enemy and this hit hurts him way more than you.
Besides that, you should consider addign some land destruction, to get rid of
Maze of Ith and similar lands.
Since you're playing Urbog,
Filth could be a good addition. With Urbog in Play and
Filth in Graveyard your whole board becomes unblockable.