(Resenting) Unchained Gigas

Lore
Unsure of the reasons, Gigas was freed by the undead invaders. He did not ponder the issue for too long, though. Taking his trusty club in hand, he tore through the foliage, striking down anyone he found. Each bludgeon was followed by a shout of "Know yer place!"

Acquisition
?

Name origin
?