Waldstein, or Wald for short (The Mystery Senior of Powerful Arms), is a playable character and the main tritagonist in Under Night In-Birth and it's updates. He returns as a playable character in BlazBlue Cross Tag Battle.
A hulking giant who has lived for more than a century, Waldstein once served the Licht Kreis, an organization which was dedicated to the protection of the Hollow Night and a rival to the Night Blade. He defected upon encountering Kuon, then the Night Blade's leader, and became the sworn protector of Linne from that point onwards, after Kuon had the Autonom Vatista to use her seventh wing to remove an overloaded EXS out of Waldstein’s body from completely turning into a Void, saving the latter’s life, yet the transformation progress turned Wald into a red-eyed hulking giant as of today. Waldstein continued to stay by her side even after the organization was ruined, in hopes to aid her end the Hollow Night and find the end she desperately seeks. As such, the duo have taken up residence in Hyde's apartment, training him in the ways of combat as their investigation continues.
Fitting for a man of his size, Waldstein boasts great striking power thanks to his EXS Ability: Hecatoncheir, the EXS of Mountainous Strength. To make best use of his thunderous punches and grapples, he dons a pair of custom-made iron gauntlets called The Destroyers, which allows him to stretch his reach out to compensate for his low mobility.