Helga

Pohjanemo, Hiidenhauta, Vedenpeitto (Mother of the Deep/North, Grave of the Hiisi, Water's Cover)

There are many names with which Helga has been known through the years they've existed. Fear is a common feeling one feels when confronted by Helga, but while years haven't washed away the spirit's reputation, Helga has slowly grown less murderous and ferocious. Truthfully, they're already rather old, slowly starting to die the way spirits die: By melting together with the area they've been keeping and guarding, by becoming one with the nature they were originally born from.
Helga's home and the location they guard is a giant's kettle (Hiidenkirnu in Finnish) so deep its water appears black regardless of the weather. Its water also never seems to dry out, thanks to the powers of Helga. This is probably for the best, as Helga used to lure and drag passerby to a watery death in their youth. The bottom of the giant's kettle is thus covered in the skeletons of the victims.

As a dying spirit, Helga's visual appearance can be described as unclear, fluid and translucent. Imagine having dry eyes and having trouble focusing on the subject in front of you, that's Helga. They can also be called slender, maybe even petite in their youth, but now hunched. Overly long algae-like fur that seems to (obviously) be wet at all times grow from the spirit's body. Helga's eyes are white with no pupils, their haunting gaze so piercing that even if you close your eyes you can't seem to escape them. And while Helga's name and delicate appearance both seem to indicate a female gender, a nature spirit like them don't have use for genders.

[RPG character from 2015 from a Finnish RP called Hukanpolku]