The Nightside series by Simon R. Green ... hopefully bringing it up on a Dresden board isn't the sort of oil-and-water that Star Trek/Star Wars can be.
Seriously, though, a lot of the creatures and characters from there would be great additions to a DF game.
To stat them out, one has to make an assumption about the general power level of one universe vs. the other. For these stats, I've generally lowballed it, since it makes the beings more usable in ordinary DF games; they don't really represent what I think those beings' true power should be. So these are built with the assumption that John Taylor in the first book ("Something from the Nightside") is an Up to Your Waist level character, who has spent 6 refresh on powers. (Note that by the current book "The Good, the Bad, and the Uncanny" he is MUCH more powerful!)
This puts Shotgun Suzie and Dead Boy at about the same, as for most of Taylor's other allies. Setting the bar this low brings the real powers down to somewhat sane levels: Razor Eddie at maybe -16ish, Lilith in the high twenties, the Lord of Thorns at a "mere" -30 or so, etc.
Generally, the critters are about as scary as they should be for Feet in the Water/Up to Your Waist characters; you may want to toughen them for stronger characters. At those levels, -8 refresh cost Harrowing are still horrifying, especially in packs, but for full-fledged Wizards and Knights of the Cross they may not be.
John Taylor
High Concept: Returning Prodigal Son of the Nightside
Other Aspects: Some Call Me a Prince; Lost in the World; Hunted by my Enemies; School of Hard Knocks; Family Legacy Haunts Me
Skills:
Good (+3): Investigation, Intimidation, Endurance, Discipline
Fair (+2): Conviction, Fists, Alertness, Stealth
Average (+1): Might, Athletics, Contacts, Presence, Survival
Stunts:
Scene of the Crime (Investigation): At a crime
scene, +1 to Investigation rolls. He arrives at
findings one time step faster than usual.
Powers:
Channeling [-2]
Marked By Power [-1]
The Sight [-1]
Soulgaze [-0]
Psychometry [-1]
Stress:
Physical: ooo
Mental: ooo
Social: ooo
Total Refresh Cost: -6
Notes: He does have actual PI skills, which are demonstrated in the books where his finding magic gets locked down (Hell to Pay and The Unnatural Inquirer) or too dangerous to use (parts of Agents of Light and Darkness, for example); thus the Good Investigation and Investigation stunt.
Channeling represents all the magic 'tricks' he possesses apart from his Sight.
Marked by Power represents that everyone knows that he is destined to be a major player, if not *why*.
Taylor's Third Eye is more expansive than the Dresdenverse Sight, so he gets Psychometry as well.
This is a basic, and very conservative, build. By the current point in the series he's acquired much greater magical skills (possibly represented by upgrading the Channeling to Evocation?), supernatural healing (Inhuman Recovery, with a Catch of silver), and expanded what he can do with his Sight (probably Supernatural Sense), and a few new mortal stunts (No Pain, No Gain, an Investigation- or Contacts-related stunt, and maybe something else); probably putting him somewhere in the general range of -12 refresh cost. His main skill increases will be in Contacts (dramatically!), Intimidation, Alertness, maybe Endurance and Presence...
His Aspects are going to change a *lot*, too. At some point "Lost in the World" will get swapped out for "I Belong With the Monsters". "Hunted by my Enemies" goes away after that gets resolved in Sharper than a Serpent's Tooth, though I'm not sure exactly what replaces it - probably an Aspect related to his troubled relationship with Suzie Shooter. Somewhere in the Lilith trilogy (Hex and the City - Sharper than a Serpent's Tooth), the "Some Call Me a Prince" Aspect changes slightly, to something like "Could Have Been King". Even the High Concept may change slightly by the end of book 10 to reflect his new, less marginalized role...
The Harrowing
High Concept: Faceless Homunculi
Other Aspects: Implacable
Skills:
Good (+3): Fists, Endurance
Fair (+2): Intimidation, Might, Athletics
Average (+1): Conviction, Discipline, Awareness
Other skills at Mediocre.
Powers:
Claws [-1]
Inhuman Recovery [-2]
Inhuman Strength [-2]
Inhuman Toughness [-2]
The Catch [+0]: unknown; we've only seen them beaten by brute force
Living Dead [-1]
Stress:
Physical: ooo(oo)
Mental: ooo
Social: ooo
Total Refresh Cost: -8
Notes: These faceless homunculi, created from human corpses, are always found in groups. If they're still not scary enough (and they're meant to be -very- scary), give them Addictive Saliva or Claws (Venomous) depending on what their needle-fingers are injecting. If further boosts are desired, give them Pack Instincts and upgrade their Toughness to Supernatural.