To outsiders, everything pertaining to the Eternal Frozen Spring was a mystery.
It had been too long, after all... Much information had disappeared in the river of time.
Especially in a place like the Underdark where fighting was just a part of daily life. History was passed down from mouth to mouth, and many books and written documents had disappeared.
Thus, even if the Underdark United Council exhausted all their means and gathered six Legends, they were still in the dark in regards to information about their target.
They only knew some basic characteristics of the Dark Specters, and they had paid a heavy price just to learn this.
In the game, Marvin had never heard about that group of Legends.
He supposed that these six had perished in their attempt to deal with the Final Ghost Mother because there was no information about these six people in the final instance of the Ice Palace.