Lu and Su are identical twin sisters who serve as supporting characters in the anime Blue Gender. Their full names are Lu Li Chang and Su Li Chang, and they are both elite Armor Shriker operators within the Sleeper Brigade, a specialized military unit tasked with fighting the insectoid Blue and assisting cryogenically preserved sleepers like Yuji Kaido. Unlike the sleepers themselves, Lu and Su are not carriers of the B-cell condition; they are normal human soldiers who have been trained to pilot advanced mecha.

The twins share a strong bond and are rarely seen apart. Their identical appearance often causes confusion among other characters, such as Yuji and Rick Kilmer, who struggle to tell them apart. Personality-wise, they are portrayed as capable and determined soldiers, focused on their mission to reclaim Earth from the Blue. Su, in particular, is noted for her skill as an operator. Lu is described in some sources as a scientist working to understand the Blue, though this detail is not consistently corroborated.

In the story, the twins serve as members of the Sleeper unit, accompanying the main protagonists on various missions. Their role is primarily supportive, providing mecha combat expertise and firepower. They interact closely with other unit members, especially Rick, and their presence highlights the rarity of identical twins in the resource-scarce future of humanity. Their development is limited, as they remain secondary characters, but they demonstrate loyalty and competence throughout the series.

Notable abilities include their proficiency in piloting Armor Shrikers, the mecha used by Second Earth forces, and their effectiveness in coordinated combat as a pair. As non-sleepers, they do not possess the special B-cell abilities that distinguish the sleepers, but their training and experience make them valuable assets in the war against the Blue.