It's a cool concept! I love Hell... let me rephrase that. I love demonology and the mythos surrounding Hell and its demonic inhabitants, so I'd be very interested in joining a roleplay rooted in either of those.

The one detail I'll criticize is the mention of the characters' "exact purpose" being "revealed with time", as in, I assume, it being an eventual discovery at some nondescript point of the roleplay. I'm all for invoking a mysterious air but be sure to understand the difference between intriguing players or failing to provide an immediate objective to keep said players invested. If you make the main motive of your game too distant or vague, activity is sure to dwindle as a result. Make sure for your roleplay the players aren't simply flung into a world and left to wander aimlessly without anything really to do. 

Something that could prevent the latter is providing a unique and fleshed-out universe players would feel driven to explore. The general setting of Hell is already bulging with potential. Based on your provided overview, placing as much emphasis on your interpretation of Hell should be one of your big priorities, as it appears to be the main appeal of the 'The Pentinents' Tale'.