This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 螧 is uncertain. It combines 虫 (insect) with 耆, but the original semantic and phonetic roles are unclear.
The left side 虫 suggests an insect or small creature, and the right side 耆 is a shape associated with age or a fin-like structure. Picture an old, wise insect with long feelers, but remember its meaning is uncertain.
For ケン, imagine Ken the insect collector examining this rare bug: Ken -> ケン, and the insect 虫 is the focus.