InuYasha

On her 15th birthday, Kagome Higurashi tumbles down a well and lands in feudal Japan, where demons are very real and very hungry. Turns out she's been carrying a jewel inside her body that every monster in the Sengoku period wants, and within about two episodes, that jewel shatters into dozens of fragments scattered across the country. Now she's stuck traveling with Inuyasha, a half-demon pinned to a tree for 50 years who has serious trust issues and an even more serious temper. Their dynamic starts as pure friction — he thinks she's the reincarnation of the woman who sealed him away, she thinks he's reckless and rude — but watching them slowly figure each other out over 167 episodes is genuinely one of the better slow-burn romances in anime. The core group they build along the way, including a fox demon kid, a cursed monk, and a demon slayer with her own baggage, gives the show real warmth between all the sword fights. Kaoru Wada's soundtrack carries so much of the emotional weight here, and it holds up remarkably well. The tone shifts between bloody demon battles and quiet, surprisingly tender character moments without feeling jarring. If you liked the historical fantasy romance of Fushigi Yuugi or Kamisama Kiss, this hits similar notes but with a harder action edge, closer to something like Rurouni Kenshin. Fair warning: there's filler in those 167 episodes, but the central story and characters earn the runtime.