Casting on Mortal Instruments has been a low-key, simple set of circumstances — someone joins, and… well, that’s kind of it. If only for one-half of this signing and the possible circumstances behind these roles, though, I’ll take the following as a slightly bigger deal. According to Variety, Kevin Durand (Cosmopolis, Lost) and Robert Maillet (Sherlock Holmes) will appear in the fantasy adventure, having signed to play a villainous pair named Pangborn and Blackwell.

Harald Zwart is directing the film, which is based on Cassandra Clare‘s young adult series of the same name. Both center on Clary Fray (Lily Collins), the newest member of a group called Shadowhunters — that is, “half-angel warriors” who secretly protect the world from demons. When her mother disappears, she and other Shadowhunters go to battle in the secret side of New York, Downworld, a place “filled with demons, warlocks, vampires, werewolves and other deadly creatures.”

I would guess Pangborn and Blackwell hail from the depths of Hell, then? Fine by me and, while I’m not too familiar with Maillet, myself, Durand is one of today’s better character actors — even when he’s in junk like Wolverine — so this choice won’t get an objection from yours truly.

Jamie Campbell Bower (Breaking Dawn) and Jemima West also star in The Mortal Instruments, which will open on August 23rd, 2013.

In the department of “no, this isn’t dead yet,” The Daily Mail (via ThePlaylist) report that 300: Battle of Artemisia has added British actor Jack O’Connell (This Is England, Skins). He’ll take a role once reserved for Jamie Blackley: “Calisto, a teen whose desire to become the heroic man/soldier his father was leads the 16 year old to become a leader of a small band of soldiers.” (Seeing as the guy was replaced by Alden Ehrenreich in Beautiful Creatures, this strikes me as a fair deal.) As of right now, he’s boning up for “the film’s kick-ass sword action” by doing some training of his own.

Strange as it is that the big-budget follow-up to a smash hit (albeit one that came out five years ago) is moving along this sluggishly, a recently-set release date means Warner Bros. and Noam Murro have to get moving with Artemisia pretty darn soon. If it’s actually worth the kickstart will be a big question mark for more than a year.

With the cast filled out by Eva Green, Callan Mulvey, and Sullivan Stapleton, 300: Battle of Artemisia hits on August 2nd, 2013.

Is Mortal Instruments coming together nicely? What do you make of Artemisia‘s development?