The Undead Set was made out of an inner armor, outerwear, a pair of pants, boots, and a weapon.
Jiang Feng had only managed to get one set after sweeping through the entire fourth floor of the Cave of the Undead. They had a very low drop rate.
His guess was all the monsters on each floor would only drop one set of equipment at different quality. The higher the quality, the lower the drop rate.
The fourth floor probably only had this White-Silver equipment set and he could only obtain it thanks to Transmute Monster. Even the weapon from the Undead Set was transmuted from the Boss.
The entire Undead Set increased HP by 3,000, Attack by 1,500, and Defense by 500. It also had three active skills and three passive skills.
One of the three active skills was an area-of-effect offensive skill. It was indeed the Undead General's Sweep the Army skill.