World Legacy Lore [Visualized]
Asilveras for Ningirsu
Ningirsu is the oldest of the three, him the older brother of Ib. His text lore reads this (Using the OCG [Japanese version] as it gives more information):
A young man who spends all his time fighting Mekkstrosities.
Even when the Krawlers living around the forest suddenly went on a rampage, he stood his ground and prevented them from breaching the barrier.
His valiant form standing at the front lines is a source of inspiration for the denizens of the forest, but he wields his spear for the sake of his sister.
From the look of his card art, he seems some-what calm and composed at most times, being the adult figure I suppose. I personally like to think of his voice as a slightly higher pitched Katakuri or All-Might (Really a higher pitched voice than any anime character with a deep voice).
(Commanding) Ib, Aurum [Or - Um], stay back and hold the barrier. Let me handle this.
(Calm) So that's a World Legacy... You sure it's strong enough to stop the evil in our world, Lee?
(Calm) It appears that my blade is the only thing that will stop these things from coming back.