In July, when the group returned from a yearlong blackout — no concerts, no social media — its die-hard fans (known as the Skeleton Clique, or just the Clique) set the internet ablaze. “Trench,” the follow-up to “Blurryface,” debuted at No. 2 on the Billboard chart this week, behind the soundtrack to “A Star Is Born.”

Despite those impressive numbers, it’s also possible you have never heard of Twenty One Pilots. That’s partly because the music they make, filled with urgent lyrics about loyalty and beating back darkness, feels laser-targeted at young people searching for answers, meaning, community or solace. (It also tells an ongoing good vs. evil narrative featuring a set of recurring characters, which listeners pick over online like Trekkies.) It’s partly because Joseph and Dun are private, low-key guys who don’t fill their social media with a splashy array of famous friends. And it’s partly because of the band’s nearly compulsive desire to stay glued to the path that brought them here today: Keep the team small. Keep the mission pure. Focus on the live show. Be earnest.

But now Twenty One Pilots are facing a host of questions: Was their blockbuster breakout a one-time thing? Can they reach the masses again with an album that’s as stubbornly, gloriously bizarre as “Blurryface” while holding on to their integrity?

“Consumers believe, including me, that if something gets all the way to them without them asking for it, then there had to have been some sort of scheme,” Joseph said. “When actually, some things just happen to get there.”

The band’s name serves as a reminder of its goals: Joseph plucked it from the 1947 Arthur Miller play “All My Sons,” in which a World War II airplane-parts supplier learns his products are faulty and sends them out anyway, leading to the deaths of 21 pilots. Faced with career options that may not jibe with their intentions, the two ask each other if a decision will be “sending out the parts.”