Saga of Tanya the Evil

When a cold, hyper-rational Japanese salaryman dies, he gets reincarnated — not as some overpowered hero in a fantasy world, but as a little blonde girl named Tanya Degurechaff in what's basically World War I Europe, except with magic. The catch? A petty god called Being X did this on purpose to force him into faith through suffering. Tanya's response is to spite the deity by climbing the military ranks and securing a cushy desk job far from danger. The problem is she's too good at her job. Her ruthless tactical mind and terrifying magical ability keep dragging her deeper into the war instead of away from it, earning her the nickname "Devil of the Rhine." This 12-episode TV series from Studio Nut has a distinctly dark, intense tone — the orchestral soundtrack hits hard, and the battle sequences mix military strategy with aerial magical combat in a way that feels genuinely fresh. Tanya isn't a hero. She's not even particularly likeable. She's a hyper-rational sociopath in a child's body waging war against both nations and the divine, and that's exactly what makes her compelling. If you liked the morally grey power fantasy of Overlord or the punishing isekai premise of Re:Zero, this scratches a similar itch but trades medieval fantasy for trenches, artillery, and wartime politics. The Rising of the Shield Hero crowd might dig the cynical protagonist angle too. Just don't expect a feel-good story — this one earns its title.