Dragon Slayer 4(Legacy of the Wizard) Dedrudeathgadedo

ドラゴンスレイヤー4 ドラスレファミリー キャラクター図鑑

Dedrudeathgadedo / デドルデスガデド

Official illust
Manual / Kadokawa guidebook

JICC guidebook

Basic info

Kadokawa guidebook
A ghost living in an old castle in Yorkshire, England. It flies freely in the air, absorbs human auras, and converts it into its own energy.
JICC guidebook
An amorphous creature with one eye. It flies fluffy and often clings to humans.

This monster is CREDITS and has a different name for each version.
In the NES ver. of the manual, the name of this is "Dedoru".