This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
膁 combines the flesh radical ⺼ with 兼, but the exact historical development and original meaning are uncertain.
The flesh radical ⺼ suggests a body part or something related to meat, but the overall meaning is unclear. Picture a piece of meat with a double-pronged skewer (兼) through it, though this is just a visual mnemonic.
For ケン, imagine a chef named Ken inspecting the meat (⺼) on a skewer (兼): Ken -> ケン.