Oswald A. Lisker is a major antagonist in the Bio Booster Armor Guyver series. He is a high-ranking agent of Chronos, the organization seeking to harness the power of the Guyver units. Lisker becomes the host of Guyver II after forcibly bonding with a unit, gaining immense strength and abilities. Driven by ambition and a ruthless personality, he is determined to prove his superiority over the protagonist, Sho Fukamachi. Lisker’s actions and tragic fate make him a memorable character in the series.