>>11841428There's two such bosses in Breath of Fire 2.
The first is a childhood nightmare boss Barubary, which is one of the biggest-bads of Deathevan's forces.
It's a forced defeat in the game's opening, but he spares you because the bad guys have a specific interest in keeping you alive to set things in motion.
You challenge him again at the end of the game as the penultimate boss, pretty close to the final boss. He gives you the option of taking him on solo (as Ryu alone), and if you accept you get the hardest boss fight in the game, but if you win he acknowledges your strength and gives you a hint about a treasure hidden in the pitch-black room you fight him in.
The other scripted loss in BoF 2 is against Tiga, a cat man warrior who leads the resistance against the St. Eva church, and falls in love with Katt, the cat girl warrior on your team.
He won't take no for an answer when he makes advances on her, and in the resulting challenge, no matter what you try you can't take him down. Unlike the earlier scripted loss, this one's not so obvious and the player is allowed to exhaust their resources trying to beat him.