The Plot: Hellboy struggles to come to terms with the comics' oft-rumoured prophecy that he may actually be the one to bring about the end of the world. He goes AWOL to search for the truth about the origins of his rocky right hand.
The Villain: The Great Beast himself.
Likelihood? del Toro has said that "the heartbreak for me is that I know how it ends and I don't know if I want to see that ending." Could he be building up to a very grim end to the saga, where he either kills off: a) his hero; or b) humanity?
Back to Hell
The Plot: An abundance of demonic activity on Earth sees the paranormal crimebuster heading back home to discover the truth about his origins, and solve what could be his grimmest mystery yet.
The Villain: It'd have to be Satan, with plenty of minions thrown in for good measure.
Likelihood? It's unclear whether del Toro would want to invest into a project with such an epic scale after his experience with The Hobbit , but we know his designs for hell and Beelzebub would be spectacular.
The Plot: Following on directly from where Part Two left off, this one sees Hellboy and Liz Sherman attempt to raise their twin sprogs, while doing a bit of freelance paranormal defence on the side (having tendered their resignations to the B.P.R.D.)
The Villain: The primary antagonists of the movie will be the troublesome twins, who have inherited a mixture of powers from their parents.
Likelihood? Though del Toro'll have to address the issue of the pair's offspring, it's unlikely he'll go down the Meet the Little Fockers route…
Hellboy does Japan
The Plot: Inspired by animated Hellboy spinoff Sword of Storms , Big Red and a selection of his colleagues from the Bureau head to Japan to investigate the case of a Japanese folklore professor who has seemingly been possessed by ancient oriental demons.
The Villain: Demons Thunder and Lightning act through the body of innocent Professor Sakai.
Likelihood? It's seems unlikely that Guillermo would cover the same territory as the (pretty decent) animated movie, though a Japanese backdrop would provide a wonderful juxtaposition with the established Hellboy style.
Meet the Team
The Plot: A textbook adventure for Big Red, but with the introduction of more characters from the Bureau, including Dr Kate Corrigan, Captain Ben Daimio, and Roger the Homunculus (a giant, alchemically-produced, humanoid being).
The Villain: The 'Almost Colossus' story would be perfect for this, as the team go on the hunt for Roger's crude, evil brother, and the even bigger homunculus he's been working on… We say stick to prosthetics, puppetry and (please) stop-motion for the behemoths.
Likelihood? GDT might not want to expand the universe whilst trying to bring it to a close.
The Plot: The Excalibur legend comes to the HB universe in this adaptation of 'The Wild Hunt'. Hellboy's latest mission brings him to England and Ireland, where he finds out that his mother was a descendant of King Arthur's wife, making him the rightful heir to the throne.
The Villain: The Queen of Blood, against whom Hellboy must lead an army.
Likelihood? del Toro loves tackling classic tales, and we reckon he'd be itching to put his own spin on the Arthur legend.
Introducing Herman von Klempt
The Plot: Taken from the comic 'Conqueror Worm', this one follows the events that transpire when a Nazi space capsule returns to Earth, having been in orbit since the days of the Ragnarok Project. It's up to Hellboy (who learns some interesting family history from an alien being) to save the day.
The Villain: Herman von Klempt, a Nazi scientist whose head has been kept alive in a jar. Oh, and his war ape sidekick.
Likelihood? There's definitely potential here, and the sci-fi element would provide a neat twist.
Hellboy: The Teenage Years
The Plot: del Toro reckons he'll have trouble dragging star Ron Perlman back into the prosthetics: "He's doing Sons of Anarchy without makeup. He's spoiled." Solve matters by casting a teen hunk du jour in the lead, and use the Hellboy Junior comics as a template.
The Villain: There's plenty to choose from, but we'd probably go with squid-man Dr Plankton Tidepool.
Likelihood? Depressingly, a teen reboot is worryingly likely if del Toro wraps things up with HB III .
The Wolves of Saint August
The Plot: Hellboy is in the European village of Griart, investigating the deaths of a number of townsfolk, seemingly killed by a wild animal. Yes, this is Hellboy vs Werewolves as he tracks down the surviving member of a cursed royal family.
The Villain: William, the sole survivor of an incident that saw his entire (royal and cursed) family trapped in a chapel and killed.
Likelihood? del Toro proved he could do vamps in Blade II , we'd love to see his take on lycanthropes.
The Hydra and the Lion
The Plot: Based on the comic in which Hellboy travels to Alaska to investigate the death of a seemingly-ordinary janitor who may have actually been Hercules living out his final days. Whilst on his search, Hellboy encounters a half-lion girl, and has to take on Hercules' legendary foe: the Hydra.
The Villians: The half-lion gal, and the mythical multi-headed beast.
Likelihood? Doubtful, as it would probably be a daunting task for any actor to follow in the footsteps of Kevin Sorbo. Though the Hydra could be a fun beast for Red to take on in a different context.
The Corpse and the Iron Shoes
The Plot: Combine the two Ireland-set tales from Mike Mignola and update them to the modern day to keep with the films' chronology. Hellboy travels to the Emerald Isle to help a couple whose kid has been swapped with changeling Gruagach, and then he has to sort out the demonic Iron Shoes.
The Villains: Gruagach, a shapeshifting pig-man, and Iron Shoes, a demon sporting metal footwear.
Likelihood? Could end up being a little too episodic for a trilogy closer, and Red already visited Ireland at the end of Hellboy II .
The Plot: Inspired by the crossover comic, this could be the launchpad for the movie career of Dark Horse Comics' Ghost, a tormented spirit who still exists in the living world. She is tricked into believing Hellboy is her enemy, and she ends up getting the pair into all kinds of trouble.
The Villain: Alal the Destroyer, the trickster who misleads Ghost.
Likelihood? Ghost could have potential as a big screen character, but she is unlikely to get her chance here as she was not a longstanding ally of Hellboy in comic lore.
Hellboy's Christmas Carol
The Plot: Based on the holiday special comic book, this portmanteau piece comprises different adventures that Hellboy has in England. On Christmas eve, he travels into an eerie graveyard and an old mansion in an attempt to give a present to a dying woman's daughter.
The Villain: The Prince of the Underworld, who has kidnapped the aforementioned daughter.
Likelihood? It's a fun story, and the magical, underground royal family has (faint) echoes of Pan's Labyrinth , but we can't see Hellboy going all Dickensian.
Attack of the Vrcolac
The Plot: Derived from a comic story, Hellboy faces a double threat. The big guy travels to Romania with his fellow investigators for a face off with vampiress Countess Ilona Kakosy, only to find that she has summoned the vârcolac, a star-devouring vamp from Eastern-European folklore.
The Villains: The pair of vampires.
Likelihood? It'd bring the trilogy to a suitably epic close, and del Toro would surely be excited about bringing the two vampires to life in a stylised Romania.
The Third Wish
The Plot: Big Red's supposed destiny as the harbinger of the apocalypse is explored further, and, tormented, he travels to Africa to seek the advice of witch doctor Mohlomi. Hellboy then travels deep underwater, and has a deep-sea adventure involving mermaids, ruins and numerous tasks.
The Villain: Underwater hag The Bog Roosh.
Likelihood? Moving the action underwater would be an intriguing direction for the series, and would open up some amazing visual possibilities.
The Plot: In this tale lifted from the comics, Hellboy is joined by Abe Sapien and Liz Sherman on a mission to explore a supernatural circus in Germany. It seems local children have been disappearing in an act of revenge for the circus's destruction at the end of the 19th century.
The Villains: del Toro could have free rein creating some uncanny carnies.
Likelihood? It'd be a decent opportunity to combine some globetrotting antics with spooky set design, and this could actually be pretty scary.
The Plot: An updating of the story 'Midnight Cowboy', in which a young Hellboy investigates the quarantined 'Hangar 7' at an airforce base in New Mexico in 1947. The movie would combine flashbacks to this episode with a present day investigation by Hellboy and team into the top-secret Area 51.
The Villains: You could have a double whammy of dodgy government scientists and alien beasties.
Likelihood? With J.J. Abrams Super 8 and Oren Peli's Area 51 both coming up, the concept might feel a bit done-to-death by the time HB III arrives.
The Plot: Aping the recent action team-ups ( Losers , Expendables , A-Team ) and trying to compete with Marvel's The Avengers , an apocalyptic threat requires the combined skills of a host of Dark Horse characters. As well as Red's B.P.R.D. colleagues, they round up Babe, Ghost, Lobster Johnson and Barb Wire.
The Villain: To warrant this epic team-up you need a pretty formidable foe, so we'd go with a re-animated Hitler with an army of undead Nazis.
Likelihood? Pretty low. It'd be hard to raise the necessary budget when the characters lack the recognition factor of Marvel's elite.