Looking Back at the Best Animated Shows That Defined 2021

I remember the exact night I stopped treating animation like a backup plan. It was late 2021, and after scrolling through endless live-action series, I clicked on an animated show just to fill the silence. That decision turned into a months-long obsession. By the time I looked up, I had worked through spectacular animated productions from Netflix, Disney Plus, Adult Swim, Hulu, and Amazon Prime. Even now, in 2026, I still think that year was a turning point for animation, proving that the medium is not just a genre but an artistic vehicle for stories that live action could never pull off.

🕸️ Marvel's Multiverse Felt Dangerous Again

Like most people, I had superhero fatigue. The MCU's live-action machine was everywhere, but I could not escape the massive cultural footprint left by Spider-Man: No Way Home. I tried What If…? on Disney Plus expecting a side dish. Instead, I got a multiversal remix that removed the MCU's constant obligation to connect everything to the next big crossover. The show borrowed famous comic storylines and added original twists, making it easy to enjoy even for someone who had not memorized every detail of the Infinity Saga. Its first season was only nine episodes, so I could pick favorites quickly. The zombie episode won me over. As a bonus, the show pushed me back into Disney Plus' vault of 90s X-Men and Spider-Man animated series.

🗡️ Demon Slayer Turned Me Into an Anime Fan

I used to think anime was not for me. Then Demon Slayer's Entertainment District Arc started rolling out on Adult Swim and Crunchyroll in late 2021, and I understood why the franchise had become a worldwide phenomenon. The choreography was not just action; it was visual music, blending modern effects with traditional Japanese animation. The Mugen Train movie had already broken records, but the Mugen Train Arc in season two added extra polish in music and animation. Playing catch-up was a thrill, and by 2026 I still chase that feeling of discovering a show that respects its audience's time and intelligence.

🧛 Castlevania Ended With Style

Video game adaptations are usually a gamble, but Castlevania on Netflix had been going strong for four years by the time its final season arrived in 2021. I loved watching Trevor Belmont's story reach a satisfying end. The series never felt like it was apologizing for being based on a game. It leaned into vampire lore, brutal action, and character work. When Netflix announced a new entry focused on Richter Belmont and the classic game Rondo of Blood, I knew the Belmont bloodline had more life in it. In a time before every studio tried to build a video game cinematic universe, Castlevania showed how to do it right.

💥 Invincible Gave Me a Darker Superhero Story

Beyond the family-friendly MCU, Invincible opened a different frontier on Amazon Prime. It was the animated counterpart to The Boys, but it hit me harder because its bright color palette disguised a world plagued by cynicism. J.K. Simmons brought Omni-Man to life as a terrifying, magnetic presence. The show understood that animated superhero stories could be written for grown-ups without losing the visual punch. Watching it in 2021 felt like reading a mature comic book in the best way. Even now, I recommend it to anyone who thinks animation cannot handle brutality and moral ambiguity.

⚙️ Arcane Was Impossible to Ignore

Arcane became the Squid Game of animation. It dominated Netflix charts and pulled in viewers who had never touched League of Legends, including me. That was its greatest trick: brilliant world-building, pristine animation, and emotional storylines that never alienated newcomers. Hailee Steinfeld's voice performance matched her Hawkeye energy, and Riot Games somehow made a show that felt both epic and intimate. By the time season two arrived later, the first season had already cemented itself as a landmark. Looking back from 2026, I still think Arcane is the best animated show of that year because it proved a video game adaptation could be prestige television.

My 2021 Animated Must-Watch List

These shows did more than fill my queue. They changed how I talk about animation. If you are still treating animation as a fallback in 2026, start with any of these five. They represent a year when streaming platforms finally let animation compete on the same field as live action, and audiences were better for it.