soft, pliable, quiver
靭 centers on flexibility and resilience: something soft and pliable, yet tough enough to return to shape. The quiver sense is a specific application—a soft leather case that yields but protects.
靭 combines 革 (leather, hide) with 刃 (blade), likely suggesting leather that is tough yet pliable enough to be cut or shaped. The exact historical development is uncertain, but the component choice fits the meaning of soft, resilient material.
Leather (革) and a blade (刃) together: imagine a soft leather quiver that yields when you press it, yet is tough enough to hold sharp arrows without tearing. That's the pliable strength of 靭.
For ジン, picture a genie (ジン) emerging from a soft leather quiver—the genie is flexible and can take any shape, just like the pliable leather.