Doctor Who - 5 Russell T Davies Era Monsters That Should Return (& 5 That Shouldn't)
6. Shouldn't - Satan
It's quite surprising that Doctor Who was even able to tackle Satan, seeing as it could possibly cause quite a bit of backlash from the religious community. However the writers were able to pull it off by naming the creature The Beast, but have no doubts, this is clearly the Whoinverse's version of the devil himself.
The Beast is one of the largest foes the Doctor has ever faced, appearing in The Satan Pit. The Doctor is but a speck on the screen compared to The Beast, yet The Doctor happily engages in a shouting match with the creature. It's nothing short of amazing to watch. But, bringing back The Beast might not be the best idea.
For a start, The Satan Pit ends with The Beast falling into a black hole. But exploring The Beast further would likely lead to a lot of the mystery surrounding the monster being lost, and sometimes less is more. Seeing a younger form of The Beast wouldn't make sense either, as he surely would've mentioned the encounter to The Doctor. It's probably for best to let The Devil rest.
It's worth noting that The Beast does return in a short comic, but once again is defeated while appearing as Martha Jones.