Fencer of Minerva

When a treacherous advisor seizes control of a kingdom, a prince gets thrown off a waterfall and left for dead, and a princess refuses to be married off to some foreign royal she's never met. That's the setup for Minerva no Kenshi, a 1994 OVA from J.C.Staff that blends political revenge fantasy with some genuinely dark mature content. Diana, daughter of the man who staged the coup, disguises herself and flees rather than accept an arranged marriage — only to get captured by slavers almost immediately. The person who pulls her out of that situation turns out to be Sho, the prince everyone assumed drowned twelve years ago, now grown up and quietly working his way toward reclaiming what was taken from him. Their dynamic carries most of the story's weight — two people on opposite sides of the same betrayal, figuring out what they owe each other. The fantasy setting has that gritty, unglamorous feel that a lot of 90s OVAs leaned into, closer to Berserk's medieval grimness than anything clean or heroic. If you've seen La Blue Girl or Urotsukidōji and know what that era's mature fantasy looked like, you'll have a reasonable sense of the tone here. Five episodes, so it moves quickly. Just go in knowing the hentai tag is accurate — this isn't subtle about its content, and that's clearly part of the package.