A while ago, Reve had commissioned a battle staff just for him.
The staff was made from a branch of the World Tree, gifted to him by Circe, and his rib bone.
It was almost suicidal to carve out his rib bone for a battle staff, but Reve was different.
He was a Frost Tree.
This was something he had come to understand after his titan's emergence.
The Frost Tree that had plagued his dreams was the perfect representation of him. It was essentially him. His insides resembled the makeup of a tree.
Sometimes, leaves would grow on his body, and he would have to work on his transformation skills to hide them.
So, Reve figured if he sacrificed a branch of that tree, it would produce an unexpected effect.
Reve contracted a forger during one of his holidays. Dwarves made the best weapons. Hence, he traveled all the way to Alfheim to seek one of them.