Late-Southern-Sòng nèidān 內丹 author of the Southern Lineage (Nánzōng 南宗), zì Yuánruì 元瑞 (also Tiānruì 天瑞), hào Zǐxū liǎozhēnzǐ 紫虛了眞子 (“Master of the Purple Void who has Realised the Truth”). A native of Fúzhōu 福州 (Fújiàn). Disciple of Péng Sì 彭耜 (one of Bái Yùchán’s most prominent followers); the discipleship is attested in Xiāo’s preface (dated 1260) to DZ 687 Dàodé zhēnjīng sānjiě (preface, 8a). For the second zì Tiānlái 天賴, see Quán Sòng cí 全宋詞 4.2777. Author of Jīndān dàchéng jí 金丹大成集 (DZ 263.9–13 = the present work in the Kanripo split), a five-juan compendium that became a standard later anthology of Nánzōng nèidān terminology and method. Xiāo is repeatedly quoted in DZ 1005 Zhōuyì cāntóng qì fāhuī (e.g., 3.3b, 5.18b, 6.2b), and his commentary on the Cuīgōng rǔyào jīng 崔公入藥鏡 is preserved in DZ 135 Cuīgōng rǔyào jīng zhùjiě. He also wrote a commentary on Lǚ Dòngbīn’s 呂洞賓 cí-lyric Qìnyuánchūn 沁園春 (cf. DZ 136). Some of his cí are reproduced without attribution in DZ 1100 Mínghè yúyīn 鳴鶴餘音 (1347). The Dàozàng jíyào 道藏輯要 edition of his Jīndān dàchéng is incomplete. No CBDB record found; the floruit follows the catalog meta and Baldrian-Hussein’s standard scholarly notice.