Five elements in a mendahk, is it magic?

[David]

Originally Posted by HughChen

Maybe that is the only answer. It doesn't belong to any Keris culture, it's something else coincidently happens in a Keris.

I would not go so far as to say it doesn't belong to any keris culture just because we cannot absolutely identify who the figure represent. I do agree with Milandro though that this is a more recent, 20th century figural carving and with more recent hilts there is a tendency for them to be less connected to identifiable characters.
Here is a hilt i have which i believe might be North Jawa, though others might have a different origin. It does bear some resemblence to your hilt in that it is an armless and legless figure with some vegetal abstraction, however it does not display the same hair style, but rather the long flowing hair that we generally associate with Buta Bajang hilts.