Without any doubts, that gigantic withered tree was none other than the past Moon Tree, which was now completely dead, while the seven spears on it were the curses of the Seven Gods.
As for the figure that was pinned on the tree, that was definitely the will of the Moon Tree.
Because it was the entity worshipped by the entire elven race, combined with its true form originally being a living life form, when it gathered enough consciousness to form a personality, its will manifested as an individual.
In reality, its consciousness was gigantic, even more so than the current Negary. If it hadn't been weakened by the Seven Gods and pinned to its dead body with the seven curse spears, its will could easily reach every corner of this world in an instant.