Permanent Midnight is a weekly Complex Pop Culture column where senior staff writer, and resident genre fiction fanatic, Matt Barone will put the spotlight on the best new indie horror/sci-fi/weirdo cinema, twisted novels, and other below-the-radar oddities.

It’d be difficult for any actor to stand out in the X-Men movies, lest he or she play a mutant whose superpower is commanding everyone’s attention at all times or growing 20-feet tall whenever they’re being ignored. Especially in the latest installment, X-Men: Days of Future Past, the star power is stronger than Hank "Beast" McCoy on the Ryan Braun diet. You’ve got Hugh Jackman and his ridiculously ripped physique muscling around as the sequel’s time-traveling hero, Wolverine, and Oscar darling Jennifer Lawrence leaving fanboys all googily-eyed as the sultry and dangerous shape-shifter Mystique, while using her Herculean acting skills to give the character endearing depth and vulnerability.

Take another look at X-Men: Days of Future Past’s poster, though, and pay close attention to the long-haired gent occupying Jackman's left pec: James McAvoy. He’s the always impressive Scot who, despite his lower profile, is the best thing about both X-Men: Days of Future Past and its predecessor, X-Men: First Class (2011), even if he's been relegated to 'Wolverine's chest' one-sheet placement.

McAvoy plays the young Professor Charles Xavier with a wry sense of humor and an inner turmoil that’s never on-the-nose, unlike, say, Jackman’s Wolverine, whose droll one-liners are funny but often telegraphed. McAvoy never signals where Professor X’s emotions are leaning. He doesn’t own the dialogue so much as live within it. In a franchise dominated by showy performances and supernaturally powerful mutants, his Charles Xavier is the necessary straight-man who keeps the larger-than-life enterprise on course.

Outside of the X-Men universe, McAvoy has been similarly overlooked in favor of his paparazzi-hounded peers. He’s from the same thirtysomething generation as Ryan Gosling and Jake Gyllenhaal, yet McAvoy doesn’t pop u in on gossip blogs. He lets his talent dictate his career and notoriety, an admirable move that’s allowed the 35-year-old actor to steadily volley back and forth between quirky indies and glossy Hollywood fare. For every X-Men or Wanted (2008) studio job, McAvoy turns up in non-mainstream oddities like Trance (2013) and prestige period dramas like Atonement (2007) or Robert Redford’s The Conspirator (2011). He’s an unpredictable character actor who’s somehow been able to land multiple leading-man parts. You get the sense that he’s signed on for numerous X-Men movies for two reasons: He wants to have some big-budgeted fun and he’s able to understand the complexity of a character like Charles Xavier.

With consistency, though, comes a lack of surprise. McAvoy is the movie biz's answer to hip-hop's Royce Da 5'9 or, going further back, Ras Kass—an excellent performer who's never transcendent. Up until now, he's yet to give that one performance which critics can look at as "the definitive James McAvoy showcase." All of the great actors have those—think Daniel Day-Lewis in There Will Be Blood, Marlon Brando in On the Waterfront, Denzel Washington in Malcolm X, and Liam Neeson in Schindler’s List. And, to a lesser degree, Tom Hardy in this year’s Locke or 2008’s Bronson.

Great news: In the deranged new indie pic Filth, McAvoy has found his own Bronson. He’s found one of the sleaziest, most reprehensible characters any actor could ever dream of inhabiting—and, because he’s James McAvoy, he makes you care about the sadistic son-of-a-bitch.

Based on Trainspotting author Irvine Welsh’s 1998 novel, Filth takes a long, unadulterated look at Detective Sergeant Bruce Robertson, a racist, misogynistic, drug-abusing Scottish bastard whom McAvoy dives into wholeheartedly and almost unrecognizably. On the clock, Bruce is hell-bent on landing a promotion to Detective Inspector. He's willing to manipulate all of his colleagues by any means necessary, whether it’s exposing insecure Ray Lennox’s (Jamie Bell) “baby cock,” sleeping with another detective’s wife, or turning a closeted co-worker against his peers. At home, Bruce is haunted by visions of his ex-wife, Carole, and their 7-year-old daughter, Stacy. To combat his mounting depression, he makes perverted prank calls to his best friend’s wife, masturbates angrily, and indulges in ludicrous amounts of whiskey and cocaine.

Simply put, Bruce Robertson is the absolute worst. He’s a monster who preys on others’ weakness and can’t stop brutalizing himself, one swig and line at a time. He’s also nothing like anyone James McAvoy’s played before, which makes his performance in Filth such a revelation.

You want to loathe the guy for forcing a 16-year-old female suspect to give him fellatio. You’re repulsed by this lunatic who gets off on auto-erotic asphyxiation during sex with another man’s spouse. But McAvoy doesn’t let you write Bruce off for those heinous actions. There’s always a sadness beneath his put-on megalomania. McAvoy conveys the character’s insurmountable pain through his eyes, those two puffy bags demonstrating little sleep and narcotics overload.

Filth writer-director Jon S. Baird presents Bruce’s descent as a hallucinogenic nightmare. There are frequent cutaways to a pig-faced man in the mirror; dream sequences involving Bruce’s therapist, Dr. Rossi (Jim Broadbent), play like some unholy combination of A Clockwork Orange and Tom Petty’s forever creepy “Don’t Come Around Here No More” music video. Not exactly a psychological horror flick, Filth opts more for uncomfortable laughs than surrealistic shocks, and it’s in that tonal consistency where the film loses its way slightly. Some overly melodramatic soundtrack cues partially derail a few climactic scenes. At times, you wish that Baird had just let Irvine Welsh’s source material be crazy in and of itself, rather than pushing his own overwrought stylishness.

Ultimately, Filth the movie is is inferior to Filth's central performance. McAvoy elevates an otherwise fascinating but uneven movie into must-see importance.

Considering that X-Men: Days of Future Past earned more than $300 million worldwide in its first four days, everyone certainly knows James McAvoy’s name now, though they already should have long before then. He’s the pre-Patrick Stewart version of Professor Charles Xavier whom Marvel Comics fans and summer blockbuster viewers deserve. Now, though, McAvoy deserves their undivided attention.

In an ideal world, one where Academy of Motion Picture Arts and Sciences members weren’t stuffy Meryl Streep devotees who frown upon daring cinema, next year’s Oscars would show a clip from Filth’s most emotionally destructive sequence: McAvoy’s Bruce Robertson looking at a freeze-framed home movie of his former wife while having phone sex with his best pal’s wife, violently going all Billy Idol while crying uncontrollably. It’s simultaneously abhorrent and heartbreaking. That you feel sorry for Bruce the whole time is indicative of James McAvoy’s own mutant-like power: He’s a chameleon who can alternate from saving the world to destroying himself, all within the same week.

Filth opens in limited theaters today and is currently available through Magnolia Pictures' VOD.

RELATED: In Locke, Tom Hardy Only Needs a Car and a Camera to Prove He's the Best Actor Alive
RELATED: Permanent Midnight: Michael C. Hall, a Mullet, and Throwback '80s Violence Make for One Badass Movie