Jack the Ripper

From Tardis Wiki, the free Doctor Who reference

Jack the Ripper was the name given to a serial killer who terrorised London in 1888. Several entities were believed to be the source behind the killings.

Potential Suspects

The Valeyard was said to have committed the killings to power the Dark Matrix. In an alternate timeline, the killings continued, leading to anarchy in London. (PDA: Matrix)

Other accounts claimed the Fellowship committed the murders to summon the Yssgaroth into the universe. (NA: The Pit)

A third account claimed the Ripper was a Re'Nar shapechanger who killed to place blame upon a rival race. It was eventually stopped by the Eleventh Doctor. (IDW: Ripper's Curse)

Jack the Ripper was believed caught by the Silurian Madame Vastra, who proceeded to devour him. She found him "stringy, but tasty all the same". (DW: A Good Man Goes to War)

Other References

Jack the Ripper