Take the band's second EP, Cairo Knife Fight II, which follows an album in 2009 and last year's self-titled EP, and its sprawling eight-minute opener The Violence of Action, the maniacal riffing of The Secrets of Sin (which Tokona christened), and The Opiate of the Living, a deep brooding beauty with the recurring mantra "feels like I'm dying here".
"Lyrically it's all very important for me too - and nothing is ever said lightly," says Gaffaney.
He wrote The Violence of Action after reading a book called The Lucifer Effect, about a bunch of Stanford University students who were made either prisoners or guards as part of a mock prison experiment in the 70s. "Within days it had to be called off because there were people hurting themselves, hunger strikes, and violence occurring. Basically it was an experiment about how human behaviour is attributed to conditions and structure rather than inherent evil."
For Gaffaney CKF II is not only a step-up in intensity, but also another step along the road of feeling comfortable bringing CKF's blistering and hallucinatory sound to life. Because it's a tricky art, with Tokona mangling all manner of riffs and loops, and Gaffaney singing, playing drums, and synth bass all at the same time.
"We get a chance to lie down in the music a little bit more, and let the big things get bigger, the wider things a little wider, and express ourselves a little more easily as a duo."
Up until II Cairo Knife Fight was more like Gaffaney's baby, with Tokona adding his twisted wares to the mix, but now it is an entirely collaborative project. Which could be the reason the chest-beating melodic rock of Weta creeps into a song like The Origin of Slaves.
CKF started out as a much bigger band four or so years ago but eventually as a duo "it just took on a life of its own as an artistic experiment".
The Christchurch-based pair are an odd couple, with the more refined and concentrated Gaffaney a stark contrast to the wilder, and self-confessed "emotional and mentally perturbed" Tokona. But it's these differences that help make the music they create together such a powerful force.
"We come from opposite ends of the world really. Personality-wise, in upbringing, and family backgrounds, but we just want exactly the same things out of the music we're making.
"And I think what we do best is stick to our knitting - he does what he does and I do what I do and we don't really muck around with each other's parts very much."
And over the years Gaffaney says they have built up a lot of trust in each other. When he first met Tokona he wasn't making much music following the messy demise of Weta in the early 2000s. The band broke up because of a combination of rock 'n' roll excess and the demands of being a professional band getting the better of them - and Tokona's battle with bipolar disorder was also part of it. "But I've taken that monster and looked it square in the eye and I've come full circle there," he told TimeOut in 2009.
"He's grown back into his role and life as a musician," says Gaffaney, "because that's obviously what he's meant to do with himself."
Of all the musical projects they have done over the years, with Gaffaney an in-demand drummer for many of New Zealand's best bands and musicians, this is the sort of music they have always wanted to make. But, he says, they are already moving on to creating new sounds and delving into new technology to make it happen. "It's ever-changing and we're wondering if we've come to the end of the big riff-based drum thing."
LOWDOWN
Who: Cairo Knife Fight
Line-up: Nick Gaffaney and Aaron Tokona
Listen to: Cairo Knife Fight II, out now
On tour: With Head Like a Hole at Bacco Room, Auckland, Sept 1; Altitude, Hamilton, Sept 2; Brewers Bar, Mt Maunganui, Sept 3
- TimeOut