Let me summarize:

In "The Swordsman", Linghu Chong and his junior sister Yue Lingshan were childhood sweethearts; Yue Lingshan fell in love with someone else;

In "The Eight Parts of the Dragon", Zhao Qiansun had an unrequited love for his junior sister Tan Po (who is also Tan Gong's wife); Zhao Qiansun was nagging, It is estimated that Granny Tan felt that Mr. Tan was reliable and stable, so she chose the latter;

In "The Legend of Heaven and Dragon Sword", Cheng Kun liked his junior sister, but married Yang Dingtian (the leader of Mingjiao); Licheng Kun always thought that his junior sister was being forced, but in fact she really liked Yang Dingtian, but after marriage, Cheng Kun hooked up with his junior sister again, what a slut!

In "Liancheng Jue", Di Yun also fell in love with his junior sister Qi Fang; but the junior sister's beauty aroused Wan Gui's lust, so he framed Di Yun and won the beauty back to himself;

Analysis: In fact, many times, brothers and sisters grow up together. Although there is friendship, it is inevitable that they will get bored after a long time, so it is easy for their love to be stolen.