A slot, a Mechanical Heart Rune Device...
Frankly, if you placed these two items in front of any Rune Expert or Legendary Mage, they would never associate them with enhancing the power of a Mechanical Undead.
But in Wei'en's eyes, this one tiny modification was enough to impact the entire Undead World. It could even subvert the Mechanical School's entire system of Mechanical Puppets and mechanical enhancement.
And that was—
Wei'en took out a palm-sized metal plate he had prepared earlier. Pointing at the dense Rune Patterns covering its surface, he said, "This is a prototype of a Rune Array Board Card I made. Inscribed on it is a Rune Array the Mechanical School was very fond of during the Fourth Era—the Iron Heart Fury Array."
The Iron Heart Fury was the first Mechanical Puppet blueprint he had learned. The Iron Heart Fury Array branded within it only had two runic effects: Solidify Heart and Fury Burst.
