It’s easy to see trans comics artist and TV creator ND Stevenson as an unmitigated success. As his autobiographical graphic novel The Fire Never Goes Out notes, he was 25 in 2015, when his award-winning independent webcomic Nimona was published as a book. That same year, he started writing for television, helped create and launch the comic Lumberjanes, wrote a Thor story for Marvel and a Wonder Woman tale for DC, and took over the Marvel comic Runaways. From there, he went on to become the showrunner for Netflix’s She-Ra and the Princesses of Power, which immediately built a strong fandom among young women.

But while Stevenson was developing and presenting this wave of strong, confidently voiced work, he was also quietly posting doodly little comic strips to Tumblr, telling personal stories about romantic rejection and alienation, depression and self-harm. Stevenson’s self-portraits often featured a giant hole in the middle of his body, which in various strips housed a flower, or emanated a self-hating specter, or filled with flames. In these mini-strips, he tracked his professional successes, personal failures, hopes for the future, and above all, struggles with feelings of emptiness and doubt.

The Fire Never Goes Out collects those strips, and functions as a spotty diary of Stevenson’s life from 2011 to 2019. It’s partly a peek behind the scenes of his public life, and partly a memoir of mental illness and recovery. But above all, it’s a strikingly personal look inside his head, or inside that gaping bodily hole where he couldn’t figure out what was missing.

The book’s many simple, sketchy black-and-white comic strips are a perfect illustration of self-doubt. Stevenson has entire pages to play with, but his self-portraits are tiny figures who talk in small, claustrophobic lettering. The characters are chunky and diminutive, with abundant white space dwarfing them. They’re simple and cartoonish, but expressive, with bags under their eyes and strained, sometimes resentful faces. Where Stevenson’s Nimona art or humor strips re-imagining Lord of the Rings characters as bar-hopping hipsters fill up screens from edge to edge with color and action, these personal comics shrink into the center of pages until they feel like small, interior voices whispering out doubts.

But the strips also show an artistic life in flux, as Stevenson plays with styles — sometimes drawing himself as angular and bendy, sometimes stylized as a shadow or a pile of ash, sometimes as a fully drawn, perky young woman, happy with her hair and clothes. The drawings come in duotones or color, shaded or in line drawings, in images randomly scattered across a page sketchbook-style, or ordered into boxes like a formal comic strip. They feel like experiments: While Stevenson works on figuring out who he is, he also works out how to tell his story effectively, and how to match images and words in a way that suits the sensation of the moment.

Stevenson is fighting a lot of battles in these strips — figuring out his sexuality (he progressed to gender-neutral pronouns on the way to transition, before moving to male pronouns and a new name), figuring out how to physically present to fit his identity at any given moment, trying to understand why he feels so hollow, navigating art school and the professional world. Fans looking for specifics won’t find many here — there are vague allusions to an ill-advised, doomed relationship, or to a mental-health diagnosis, but they’re generally couched more in poetic and artful language than in concrete facts. (One chapter detailing a relationship is literally a mixtape, with art fitted to selected lyrics telling an emotional story.)

Similarly, The Fire Never Goes Out isn’t the kind of in-depth memoir where behind-the-scenes story fans are going to learn what went into developing She-Ra or laying out the story beats in Nimona. Chapter brackets laying out the transitions from one year to another often list Stevenson’s achievements and check in on the feelings of the moment, but much of the rest of the book feels like an emotional highlight (and lowlight) collection from an Hourly Comic Day, focused on shifting feelings and occasional quotidian moments.

But the book feels raw and personal in a way that eclipses the usual structure of a memoir. It’s an open admission that an illusion of strength and competence can hide a core of insecurity, and that even the most talented creators can struggle with feeling like frauds. There’s a winsomeness to Stevenson’s version of a confessional — his cartoon self-portraits are nakedly vulnerable and hurting, but also frankly adorably drawn and appealing. And readers who’ve followed Stevenson’s career and identify with him in any way — particularly his most expressive core audience, of young, questing queer and trans people who are similarly finding themselves — are likely to connect not just to the message, but to Stevenson’s distinctive, self-effacing, artful way of communicating it.

A great many of Stevenson’s self-portrait comics revolve around that idea of something filling the hole in his chest. In one strip, it’s an angry monster hiding inside him. In another series, jagged crystals form out of his sternum, to represent his heart hardening in protective ways that sometimes stab and wound other people. In another series (“I am on fire … literally on fire all the time,” it starts), Stevenson works calmly and with a straight face, while flames jet out from his center, and captions like “aaaaahhh” and “oh my god oh my god oh my god” signal the distress he isn’t expressing.

But on another page, those flames are portrayed positively, as a sign of inner ambition and power. The joys and tragedies of The Fire Never Goes Out all come down to that recurring image: the idea of something hidden that Stevenson is trying to process and express. This memoir is a way of letting other people peer into his unseen personal world, and see themselves there as well.