The lake is a natural dam formed by the collapse of one of the summits back in 1838. In German the Lake is called Mördersee (Killer Lake) and Hungarians call it gylkos (murderer).
When the summit collapsed, a complete village was covered by lake waters killing all people and creatures in its way. The legend says that the water was red with the blood of the victims, hence the name Red Lake.
Romantic legends are also tied with the name of the lake, but we will leave it to you to discover while in the area.