This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
鉝 is a rare character combining 金 (metal) and 立. The exact historical development is uncertain, but it likely originated as a phono-semantic compound with 立 contributing the sound.
The kanji has no clear meaning, but visually it shows metal 金 standing beside 立. You might imagine a metal stand or a standing metal object, though this is speculative.
For リュウ, picture a metal 金 stand 立 used by a dragon (りゅう). The dragon's roar cues リュウ while the metal stand holds its treasure.