System of a Down is a heavy-metal band that can do fury and aggression with the best of them. And yet here is Daron Malakian, the chief architect of the group's sound, shuffling into the 1st Mariner Arena dressing room, shoulders slumped, face drooping, eyes averted, as if he's the most timid person in the building, if not the entire Inner Harbor. He nods at a visitor, then meekly extends his arm and offers a totally un-rock-and-roll handshake, a sort of dead fish with fingers.

His assistant appears more self-assured than Malakian does. So do the System roadies, the band's personal chef, Malakian's leggy fashion-model girlfriend, the tour-bus driver -- even the woman selling hot dogs at a concession stand upstairs on the fan-filled concourse, where the hair is long, the testosterone is thick and the dress code calls for black T-shirts celebrating this god of thunder (Iron Maiden) or that one (Metallica).

Oh, if only the belligerent kids could see the new metal deity, Malakian, right now, in the arena's bowels. System's guitarist, part-time singer and principal songwriter -- the man behind the majority of the Los Angeles-based Armenian American quartet's lyrics and melodies, not to mention some of the most unconventional arrangements to reach the top of the Billboard charts in ages -- is slouched in a ratty armchair, appearing fragile, shy and not a little uneasy. Speaking so softly that it's hard to hear his quivering stoner's voice over the hum of an air-conditioning box, Malakian addresses the dichotomy of his System of a Down persona and his downtime self.

"It's crazy, like a complete Jekyll-and-Hyde syndrome," he says, two hours before System takes the stage for a set of artsy, idiosyncratic hard rock that defies tidy definition. He shrugs almost apologetically, then takes a drag from a small pipe packed with weed. "It's like Prozac to me -- it takes the edge off," he says. He is wearing a T-shirt that declares: "Hard drugs made me a better person." He is also wearing metallic-silver sneakers. He is slight and relatively short, with a boyish face lined with a C. Everett Koop-style beard.

While Malakian might seem like a man in need of a self-help book, or at least a pep talk from Stuart Smalley, he needs none of that in the studio or onstage, where he's bold, brash and cocksure.

Just watch him later on this hot August night as he shrieks into a microphone, his posture straightened, his bloodshot eyes popped open like a bug's as he glares at the crowd, which he antagonizes with obscene gestures that, in the calculus of hard-edged music, have a funny way of strengthening the artist-fan bond. His guitar riffs occasionally reach breakneck speed (not to mention ear-shattering volume) and have the overall effect of whipping the audience into a frenzy, particularly in that elbows-up caldron of rage known as the mosh pit. Even the Armenian-flag-waving fans in the green zone of reserved seating can't help but thrash about.

A similar sneering attitude comes through on System of a Down's studio albums, the newest of which, "Hypnotize," will be released Tuesday. (It's the second part of an adventurous double album that the band sliced into halves. The first, "Mezmerize," was released in May.)

"I don't think when I'm doing music," Malakian says backstage. "Things just happen. I've even taken my clothes off while performing. But then I'm so shy that I can't even take my clothes off in the dressing room, even though it's just the other guys in the band in here with me. It's really weird."

Which pretty much sums up System of a Down.

Though hard and heavy at its core, with a strong sociopolitical foundation (Michael Moore directed one of the band's videos), System's music is also funny, satirical and singularly bizarre. The group, which suggests the Mothers of Invention headlining at the Headbangers Ball, has a penchant for spiking even its thrashiest songs with pretty pop melodies, circus-opera flourishes and Middle Eastern and East Asian instrumentation, not to mention tricky time signatures, unusual chord progressions and the occasional oddball lyric such as "gonorrhea gorgonzola."

A System-listening experience, then, might go like this: One moment you're pummeled by speed-metal riffs, a furious kick-drum assault and a howling rant about hypocrisy and war; the next, you're humming along to a buoyant pop-reggae chorus about "going to the party" (in the desert) and having "a real good time" (at war). Then the hammer drops again, and the tempo shifts, and the thrashiness and cartoonish vocal absurdity resume, and the song eventually just takes you to the land of the berserk.

And yet, despite its inherent strangeness, or maybe because of it, this song, "B.Y.O.B.," became one of 2005's biggest rock-radio hits.

"We're still playing it," Jim Fox, station manager for KRXQ-FM in Sacramento, says of the single, which System performed in May on "Saturday Night Live," adding an expletive in the live-TV process. "I think the weirdness is a lot of the band's charm. There's a lot of sameness [in rock]. . . . System of a Down really stands out because it sounds so different."

The band is one of the more unlikely success stories in post-millennial popular music, with two consecutive albums -- 2001's "Toxicity" and this year's "Mezmerize" -- entering the Billboard chart at No. 1.

"It trips me the hell out," Malakian says of the band's success. "We don't make easy music, so it's kind of crazy to be here."

In a separate interview, System's lead singer, Serj Tankian, says: "We always knew people connected with our music. From Day One, even before we toured or got signed, before 'Sugar' [the band's first important single, from 1998], the music seemed to touch people in an honest and raw way. But no, I didn't think we'd do these kinds of numbers."

Tankian and Malakian formed System in 1995 with drummer John Dolmayan and bassist Shavo Odadjian. They were four guys in their 20s with disparate musical interests (Depeche Mode, Chet Baker, Christopher Cross, Madonna, etc.) but a shared love of hard and heavy rock. While cutting their teeth on the Southern California club circuit and watching other bands with less local success land fat recording contracts, System of a Down was, according to Malakian, told by various music-biz suits that to succeed, the band needed (a) a new lead singer and (b) stronger pop hooks, even though (c) it might be impossible to market them to the mostly white metal audience because (d) the musicians were, you know, so Armenian and (e) too weird, anyway.

Eventually, System signed with the visionary producer Rick Rubin, and the band made its major-label debut on his American Recordings imprint. The operators of the industry propaganda machine at Columbia, which distributes American Recordings, cast the band as a nu-metal outfit. The tag didn't make much sense, since System wasn't aligned stylistically with the Deftones and Tools of the world. Still, the mislabeling may have been a blessing for the band, says Brad Tolinski, the editor of Guitar World.

"These guys were grouped in with bands like Korn and Limp Bizkit, and they were able to sneak in under the wire because of those affiliations, even though they didn't sound like them," he says. "And when nu-metal got cleared away, System of a Down was still standing. It was a neat trick. They were clearly able to create their own identity and unique sound."

Here's what System isn't, says Tankian: "We're not the Armenian Rage Against the Machine. Yeah, we have some political songs, but we have more that are about love and life and sex and pogo-stick orgies and all that." There are also entries in the System songbook about, among many other things, Armenian genocide ("P.L.U.C.K." and "X"), media brainwash ("Violent Pornography"), drug possession penalties ("Prison Song"), riot police ("Deer Dance"), war ("Cigaro") and Tony Danza ("Old School Hollywood").

None of which helps anybody put together a neat, pithy description of whatever it is that System of a Down does.

"I've heard us called a wacky, crazy, political Armenian art band," Tankian says. "I guess I'll take that one after 10 years."

Says Malakian: "I even have a tough time explaining the music myself. If you ask six different people, you'll get six different answers."

Gilbert and Sullivan at Ozzfest, for instance.

And yes, that's a good thing: "Mezmerize" is one of the year's more inventive, brave, urgent, captivating and interesting hard-rock releases. It's all of that, and it's good, clicking on both an emotional level and an intellectual one.

Mosh first, ponder later. Or vice versa.

"I don't believe in thinking-man's music," Tankian says. "I believe in music that's instinctual. When people are listening to music, they're not thinking; they're feeling. You may not necessarily agree with the premise of an antiwar song like 'B.Y.O.B.,' but you might connect to the satire and the power of the music."

Tankian is everything and nothing you expect of a rock god. He has fabulous hair that would make Robert Plant jealous, and he's a charismatic singer, with a swooping, wild voice and a magnetic stage presence. He's also meditative, soulful, spiritual, worldly, personable and outspoken (not to mention political, as he's partnered with Audioslave and former Rage Against the Machine guitarist Tom Morello to create the youth-oriented activist organization Axis of Justice). But Tankian plays air guitar in the middle of songs (which is so dorky and uncool that it's almost somehow cool), and he has the audacity to smile warmly for the camera during photo shoots, in clear violation of one of rock's most important commandments: Though Shalt Not Show Teeth (Save for a Grimace).

"It's a choice," he says. "I get a lot of photographers that say, 'Okay, now give me your mean look.' I crack up. What does that mean? Why should our type of music, whatever it is, have some type of mean look associated with it? Why can't heavily charged music be positive and funny? I mean, I pretty much laugh and smile throughout our sets; that's how I get by. That doesn't mean I don't get serious or zone out and go to deep places in a performance. But we can't take this too seriously. It's just music and life."

For Malakian, those things are essentially one and the same. Rubin calls him "a special artist and person," but the producer has also said that Malakian exists in a bubble filled with music, that he doesn't have much of a life outside of his art.

Whereas his three band mates are comparatively well-rounded with hobbies and actual social interests and even spent the day of the Baltimore show goofing off in New York, Malakian arrived at the arena at least four hours early and ate hot dogs and Doritos and chatted with his girlfriend and the band's crew and talked and talked about music, which is his usual road routine. At home in Southern California, where his only real hobby, he says, is collecting Charles Manson ephemera and human and animal skulls and skeletons, it's basically more of the same, sans the crew and maybe the girlfriend, who lives in Manhattan.

"What Rick said about me, he's not completely off," says Malakian, who grew up on a seedy street in Hollywood, the son of artistic parents. (His mother is a sculptor and his father a painter and occasional System contributor, having created the cover art for "Mezmerize" and "Hypnotize.") "A lot of people might take that and say that I'm probably depressed. That's not the case. I mean, I am depressed sometimes, but it's not what keeps me at home or focused on work.

"I'm a really religious person when it comes to what I do. I make music, and I spend a lot of time focusing on it. . . . I started collecting records when I was 4. It was something that picked me; I didn't pick music."

Though casual observers often assume that Tankian is System's principal creative force, given that he stands front and center, it's really Malakian, who is something like Pete Townshend to Tankian's Roger Daltrey (even if Tankian does write some of System's songs). And, anyway, the spotlight is starting to shift: Malakian assigned himself a larger role on "Mezmerize" and "Hypnotize," doing more singing and even playing a bit of bass on the two albums.

Malakian's new prominence has set off some hand-wringing among the band's fans. To which the man himself says: Oh, just stop it already.

"My contribution to System has been pretty much the same for 10 years," he says. "This is a four-piece rock band, and I'm the guitarist. I've also written a lot of the melodies and lyrics for our past songs, and I've done a little bit of singing. But now people are like: 'Because Daron's singing more on these two albums, it means Daron and Serj aren't getting along.' That's not the case.

"Those people don't know our history. When we first met, Serj was a keyboard player and I was a singer. But I didn't want to be the band's vocalist. That's not my gig, you know? . . . It's just been a natural progression for the band. It's not that I don't want that [expletive] Serj singing anymore and we're breaking up."

Here, Malakian laughs. It's not nervous laughter. There's just something funny about the thought, he says, of life without System of a Down.

"It's a family," he says. It's a cliche, but he has a point to make.

"Of course we get angry at each other. We've physically fought. And I think a lot of things that have happened between us might have broken up other bands. That's where being Armenian comes into play, because it makes us feel like a family. We see that we're in a unique situation. No other Armenians have ever done this. That Armenian pride will never go away, even if we wake up one day and hate each other. Which isn't the case."

Tankian agrees: "We're all very different, but our cultural similarities have helped keep us together."

About 30 minutes have passed since Malakian first dragged himself into the band's dressing room, where the shoes and socks and shirts are laid out just so, and the water bottles are placed in pairs He's been smoking himself silly since entering the room, and he's finally starting to loosen up and emerge from his shell.

He's cracking jokes about his unlikely affinity for disco and the Dire Straits (whose "Sultans of Swing" he'll later cover in concert), and he's recalling how he recently heckled Atlanta Braves fans at a Dodgers game, and he's noting with no shortage of glee that he has one of the worst diets possible for somebody with a personal chef at his avail.

When his assistant drops into the room on a rescue mission, Malakian shoos him away. He's got a lot more talking to do.

But he never does summon the sort of aggression or anger heard in his music. Not even an hour later, when a visitor's shoe hits the coffee table the wrong way, sending the lid flying off of some sort of ceramic skull doodad. It breaks into several pieces, one of which Malakian picks up. He studies it, his head cocked quizzically to the left. He looks you in the eye as he delivers his verdict: "I don't know what the [expletive] that thing is, anyway. I guess they were just like, 'Hey, Daron likes skulls. Let's put a bunch of skull crap in here!' So who cares? Not me!"

He cackles, then takes another drag.

Meek offstage, System's Daron Malakian whips fans -- and himself -- into a frenzy playing heavy metal with a political bent.Calm before the storm: From left, System of a Down's Serj Tankian, Daron Malakian, John Dolmayan and Shavo Odadjian before a concert.Drummer Dolmayan during a performance at Baltimore's 1st Mariner Arena. Like his band mates, bass player Odadjian is of Armenian descent. Political messages often figure prominently in System's songs.The mosh pit becomes a bit much for one concertgoer, who gets a boost from security.