OVA
Description
Sanae Dekomori, a junior high student, forms a steadfast alliance with Rikka Takanashi after bonding over online debates about parallel worlds. Embracing her chūnibyō persona, she brandishes twin tails adorned with weighted pouches dubbed "Mighty Mjolnir Maul," theatrically asserting their power to "make men meet their mortality." As Rikka’s devoted subordinate, she zealously pursues the "Ethereal Horizon" and the elusive "real" Mori Summer—later unmasked as Shinka Nibutani, whom she dismissively brands "Fake Mori Summer" due to lingering distrust.

Academically precocious, she mastered junior high mathematics early and clinched top honors in high school entrance exams. Her blend of eccentricity and approachability earns peer admiration, securing her position as a popular freshman class representative. Privately, she begrudgingly consumes milk daily to combat her height-related insecurities, despite a strong distaste for it.

Hailing from affluence, her upbringing features a chauffeured sedan and a fortified family estate, a backdrop that coexists with her fantastical roleplay. Over time, confrontations push her to grudgingly recognize the imaginary nature of her delusions. Complex dynamics with Shinka oscillate between rivalry and uneasy alliance, punctuated by accidental kisses and shared moments—such as bed-sharing with a negotiated boundary she eventually breaches—hinting at unspoken mutual fondness beneath their denials.

Later promoted to student council president, she reluctantly harries Rikka and Yuuta under threat of blackmail, showcasing her evolving leadership amid lingering quirks. Seasonal arcs trace her juggling academic rigor with loyalty to Rikka, mediating conflicts and bolstering friends’ bonds.

Her speech peppers "-desu" with a deliberate echo of "death," a linguistic flourish mirroring her chūnibyō flair. This verbal tic, coupled with her spirited clashes with Shinka, persists even as she navigates maturity and incremental acceptance of reality.