After the trio Rainer Maria plays its final two shows in New York this weekend, it will disband as one of the more mistakenly labeled emo bands in rock ‘n’ roll. It made its debut in 1995 in Madison, Wis., sincerely embracing the loud/soft dynamic shifts and viscerally naked lyrics that reductively defined the late 1990s bellwether indie-rock genre. But where and how the band extrapolated that sound during the next 11 years earned the outfit its critical acclaim, established its die-hard fan base, and charted one of the more unlikely success stories in indie rock.

Rainer Maria actually found its musical sweet spot but three songs into its debut album, 1997’s “Past Worn Searching” (Polyvinyl). Over William Kuehn’s steady drum pulse of “Viva Anger Viva Hate,” the band’s two vulnerably voiced vocalists — bassist Caithlin De Marrais and guitarist Kyle Fisher — threaded together their instruments’ slightest thumps and strums as their sotto voce harmonized exhales: “there’s no forgiveness / there must be something more.” The music complemented the lyrics’ vague longing and hovered in this seductive limbo for more than a minute until, cued by a spine-straightening distorted guitar chord, the song roared to agitated life and Ms. De Marrais bridled against her demur voice and defiantly erupted, “I’m convinced, regardless of all the times / they said that I should forget everything.”

For the next decade, the trio mined and refined the opposing tensions encapsulated in “Viva Anger Viva Hate,” finding emotional ripples between the soft and the loud, between male and female, between heartbreaker and heartbroken, between victim and avenger. On the band’s next four albums, it knitted a plush, varied landscape of ruminations on romantic disappointment hung on persuasive melodies and clamorous rackets that surge to skin-tightening, anthem-like crescendos.

But don’t dismiss the trio as mere emo. On the surface, Rainer Maria’s knotty, pretty songs do traffic in the sort of naked, interpersonal lyrics that remain emo’s core values. But the band has also managed to set itself apart from the homogeneous norm, refusing to settle for emo’s pure spleen and ideal, finding its melodrama in economical storytelling rather than confessional angst. And Ms. De Marrais’s vocal presence always added extra dimensions to the band’s music that the narrow halls of emo could never rein in.

Yes, adding one woman into emo’s predominantly male mopefest does make all the difference. Ms. De Marrais’s slightly awkward voice, which rapidly improved in range and ability during the band’s five albums, alternately haunts the band’s down-tempo moments like a specter and slices through the noisy catharsis like a gorgeous bullet, a fist that lands like a kiss. Her delicate clarity makes an ideal foil for Mr. Fisher, whose voice, at least early on in the band’s career, actually sounded the more confident. Their interplay and harmonizing turn emo’s sexual longing into sexual tension and enable the band to tell multicharacter stories, rather than constantly vent from a self-pitying first person.

The band first began to capitalize on this bristling, anxious interplay on its second album, 1999’s “Look Now Look Again.” On the mid-tempo “Feeling Neglected?” Ms. De Marrais sighed, “Halfway home and ready to turn around / but I can’t turn around my dream,” an opening verse that is practically overlaid onto Mr. Fisher’s, “Five days a week I go to sleep at dawn / and feel alone although you’re warm.” The song trades these two perspectives on a crumbling relationship and flowers into its chugging chorus, where Ms. De Marrais and Mr. Fisher unite to come apart with,”I’m feeling neglected anyway / it’s the reason I’m leaving you.”

The trio made such insightful, almost Carveresque misanthropy its stock and trade. And its musical complements to such increasingly economical storytelling matured accordingly. Rainer Maria’s third album, “A Better Version of Me,” found Messrs. Fisher and Kuehn crafting gossamer-fine melodies to back Ms. De Marrais’s now fullthroated, robust voice.

It wasn’t until 2003’s “Long Knives Drawn,” however, that Ms. De Marrais came predominantly to the fore. She owned the albums captivating hotblooded lead tracks,”Mystery and Misery” and “Long Knives,” which freed Mr. Fisher to explore some of the more acrobatic guitar work in his career.

By this year’s “Catastrophe Keeps Us Together,” Ms. De Marrais had become the sole vocalist and the band had polished its jittery agitations into a plush sound as smartly tempered and finely wrought as Blonde Redhead. For 10 years, as other indie darlings rose and fell around it, Rainer Maria performed around the world, moving from small clubs to large halls with its high-energy shows while remaining loyal to its medium-size independent label, Polyvinyl (“Catastrophe” appeared on the band’s own Grunion imprint). So while Rainer Maria’s musical surfaces suggest that it is one of the last of the 1990s emo acts still standing, its career proves that it graduated from such ranks, in which it never truly fit in, long ago, leaving it in a class unto itself.

Bowery Ballroom, Friday, December 16, and Northsix, Saturday, December 16.