Vin Diesel plays a gruff, no-nonsense loner with (actually, for once) magical abilities to kick-ass and not die. I feel like The Last Witch Hunter is actually an attempt to logically connect all Vin Diesel films, ever, into one long continuing franchise about an immortal man. Something that would start with being a witch-hunting Viking and end with him killing weird bat monsters on an asteroid in space.
If you think that premise sounds utterly ridiculous, probably give The Last Witch Hunter a miss. There's nothing ostensibly wrong with the film, but there's also nothing ostensibly right with it either. It exists. That's about it. The cast is ridiculous given the plot. Getting both Elijah Wood and Michael Caine to appear in this movie is arguably the greatest evidence that witches live amongst us I've encountered, but the film definitely benefits from the misuse of black magic to achieve this end. No performances are stellar or unmissable, but they're all better than the source material calls for. Probably the most interesting is Rose Leslie, better known as the Wildling with Flaming Hair (Ygritte) from Game of Thrones. Again, this isn't a performance that will be remembered through the ages, but it is one which will hopefully pique some other director's interest. I'd love to see her in a more stretching role one day, I think it would go pretty well.
Less notable is who-ever plays literally anyone else. The blind warlock is a fun character, though introduced as a walking (but not very effective) ex machina to move the plot along. Otherwise, the actual bad guys are pretty forgettable. The witch-queen herself is creepy but already looks quite dated as an effect and her henchmen are barely around. There is a weird cameo by Joseph Gilgun, a brilliant actor who is utterly wasted on a couple of lines of dialogue. Everyone else basically has a single scene then is either killed or never mentioned again.
The plot suffers from similar levels of skin-deep padding. The big 'twist' with Wood's character is far too heavily telegraphed so was pretty expected but also falls foul of too little world-building, making his death feel almost irrelevant. Other major plot points turn up and are then forgotten with an air of wantonness that feels almost absent-minded. Oh, we've got Vin Diesel into a situation where he's drugged? Let's give the female companion dream walking abilities. Why wouldn't the other witches prevent that from happening? Make it slightly taboo and rare. It just seems like they had a rough draft of a story and just ran with it.
Which is a shame, because some elements of the world-building are quite cool. I liked that we have a world where witches and humans live side-by-side in an almost symbiotic relationship. Sure, there's a huge amount of borrowing from Harry Potter going on here, but it feels different enough to work. The witches keeping their age a secret with gems (no explanation given) is interesting, as is the parliament of witches that keep the peace with the humans. I even like that the original plan is to create a plague that wipes out human life, but nothing really gets enough time to work. The witch-queen implies that humans are the usurpers but what does that make her? Are they just magical humans or an entirely different race?
Weirdly, based on the ending scene, it looks like someone was hoping for it to spin-off into a new franchise. A sequel has clearly been set up and I'd be lying if I said I wouldn't watch one. I'd like to get a more detailed look at that world, at the very least, plus I quite like where the characters were left. I wouldn't pay to see it, either at the cinema or on DVD, but I would definitely watch it. For free. When I wasn't that busy.