Human Sealing Technology

Human Sealing Technology is a technology installed in some Duel Disks allows winners of a Duel to seal the losers into cards. This technology is mainly used by Duel Warriors of Academia and members of the Resistance. During the Invasion of Xyz Dimension, it is seen being used against innocent non-Duelist habitants.

Process
When a Duelist is defeated, the winner hits a button on his Duel Disk, which emits a purple light that covers and dissolves the loser. A blank card with an image of the dissolved duelist is then released from the Duel Disk.

This process seems to be irreversible by LDS's technology. Serena and Shun, who themselves used the technology, showed no attempt to release their LDS's victims after they joined the Lancers, suggesting that not even normal members of Academia and the Resistance have ability to undo it.

Of Academia
By the Obelisk Force By Serena By Sora Shiun'in By Yūri By Juvenile Officers By Dennis Macfield By Battle Beast By Leo Akaba
 * Citizens of Heartland City (by Duel Warriors)
 * Ashley
 * Bram
 * Carl
 * 7 unnamed 'Youth' class Duelists
 * Michio Mokota
 * Teppei Tairyōbata
 * Hokuto Shijima
 * Hikage
 * Halil
 * Olga
 * You Show Duel School Students
 * 
 * Yūshō Sakaki
 * Asuka's friend
 * Himself
 * Bernie
 * Ted
 * Tsukikage
 * Emma
 * Jacob
 * Crow Hogan (Returned)
 * Doctor

Of the Resistance
By Shun Kurosaki By Kaito Tenjō
 * Marco
 * Tio
 * 3 unnamed LDS elites
 * An unnamed Academia Soldier
 * 6 unnamed Academia Soldiers