This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
蠉 combines 虫 (insect) with 睘, which likely contributes a phonetic element. The exact historical development is uncertain.
The left side 虫 suggests an insect or crawling creature. The right side 睘 is complex and obscure, but together they hint at something small and creeping.
For ケン, imagine a tiny insect crawling like a ken doll: ken -> ケン, and the insect 虫 is the focus.