For many musicians, going on tour is a lot like going to war. They’re always on the move through alien lands, enduring loneliness and long bouts of boredom punctuated by bursts of through-the-roof adrenaline. Or at least that’s how it was for By the Bull leader Nick Brewer.

Sometimes they’re casualties, and in Brewer’s case, those casualties were his relationships with his band the Memorials and his then-girlfriend. With the Memorials, things were so bad that his bandmates were reduced to soliciting his whereabouts through social media after calls to Brewer went repeatedly unanswered.

“I was gone [on tour] for seven months straight, and then when you get back from that kind of shit, you have to unwind. I didn’t have any space to unwind. I was still crazy wound up from the tour, and then my girlfriend and I split,” Brewer recalls. He returned home to Columbia, S.C. and dropped out of sight. “It was going to be a month or two, and that turned into a few years. It really took me that long to recover from the shit.”

The Memorials replaced Brewer and recorded another album while he tried to pick up the pieces. Enlisting a couple of local buddies, he turned the anguish and heartbreak from that period into By the Bull and its 2012 debut Ghosts & Prophecies. The album retains some of the Memorials prog elements and mixes it with bruising rhythmic tensions that suggest the chunky churn of post-punk and math rock, as well as flashes of gnarly, almost grungy guitars.

“I’m a huge Soundgarden fan. All my life I wanted to be Kim Thayil,” says Brewer. “They have a lot of odd time signatures. And that desert sound where it’s like you’re tripping on mushrooms — I’m into that. It’s one of my main influences, but I also love the Deftones and Poison the Well.”

While Ghosts & Prophecies is firmly within the arty hard rock canon, it spans the spectrum. There’s the hard-charging epic “Pigs,” which starts off as a near-hardcore tune before it ends up winding through a spacey maelstrom worthy of Weather Report. “Golden Rule” opens with some pretty guitars and gentle drift before things turn aggro; dreaminess and muscularity compete from moment to moment, creating something at once creamy and gritty.

In November, By the Bull released its follow-up, a five-song concept disc that explores Brewer’s lifelong battle with sleep paralysis. He often awakens only to discover his body hasn’t joined him. During these anxious moments, it’s not uncommon for sufferers to experience malevolent hallucinations like there’s someone in the room seeking to do them harm, and they’re unable to flee. One of the first times it happened to him was when he was in the sixth grade. When he finally regained the use of his limbs, he ran screaming to his mother, telling her he had a witch riding his back. Inspired, Brewer decided to call the album, The Witch.

“I use it as a metaphor for different things, like a break up, to focus on the feeling of being paralyzed and in a dream where you’re not being able to do what you want,” he says.

But that’s not the only metaphor that Brewer toys with on The Witch. Take the song “Empires” for instance. “There are some sexual overtones in ‘Empires,’ which is kind of about blow jobs, but you know that’s on the surface. For me, a deeper meaning for music and arts in general is how you can feel suffocated.

“The thing is the dream is going to kill you or you’re going to conquer it,” he continues. “That’s how I feel. Either I’m going to be successful at music, or I’m going to go down with the ship.”

Brewer came to music the way many young men do — through an older brother. When Brewer was young, he’d sneak into his older brother’s room to play. Eventually, his brother gave the guitar to him. After high school, Brewer attended the Berklee School of Music in Boston for a year before bailing on it, describing the school as “a machine.”

While kicking around Beantown, he crossed paths with Thomas Pridgen, who at age 10 had become the youngest drummer to ever be endorsed by Zildjian. He was also the youngest musician to receive a scholarship from Berklee when he was 15. Together, they formed the band Sabai, but Pridgen got an offer to drum for a boy band and left for California. A little later he joined Mars Volta. Four and a half years ago he called Brewer and asked him to join the Memorials.

“He was like, ‘Hey man, come out next month and let’s do a record,” Brewer says. They began recording the day after he arrived. A month later when the record was finished, they went right out on tour. “It was 17 or 18 hour days, for weeks straight. I was like, ‘The guy is trying to kill me.’ But that was a rad experience. It was just non-stop creative. ‘Give me a riff. Play me another one.’ All day long. It was dope.”

Brewer still has regrets, but he has learned to live with them. And the relationship with the Memorials wasn’t irreparably damaged. Just an hour before we spoke, Pridgen had invited Brewer out to record on their third album.

Meanwhile Brewer continues to work on By the Bull, which is now searching for a drummer. It’s another frustrating setback, but Brewer knew what he signed up for. While the search continues, he’s working on videos for the EP’s five songs, which he hopes to turn into a mini-movie.

“That’s the log I’m holding onto, trying to keep the fire going,” he says. “You just keep moving forward because you can never tell what will happen or when.”