Oswald A. Lisker is an antagonistic character from Guyver: The Bioboosted Armour. He is the second of the three Guyvers in the series.
Agent of Cronos
Lisker is an Inspector for the insidious Cronos organisation. His job within the organisation is to observe the activities within different branches and report on said activities to Cronos' headquarters in Arizona. During the series, he arrives in Japan to supervise the transfer of the Guyver units from Cronos Japan to HQ, only to find that the units have been stolen.
Although highly skilled in martial arts and trained in military combat techniques, Lisker hadn't undergone Zoanoid optimization. The reason for this is unknown, but it can be assumed that Cronos had yet to configure a Hyper-Zoanoid form suited to Lisker's talents.
Becoming a Guyver
Cronos Japan were successful in recovering one of the lost Guyver units, but it had been damaged during retrieval; another unit had been activated by a civilian and the last one was still unaccounted for. Genzo Makishima's staff were ready to begin analyzing the recovered unit, but Lisker demanded to inspect the unit more closely. He entered the lab and stood in close proximity to the G-unit and the damaged device detected his presence and activated. Lisker suddenly found himself enveloped by the unit's many tentacles as they fused with his body, quickly transforming him into the Guyver-II.
Because of Lisker's brashness, studying the dormant unit was now impossible, but new opportunities had arisen and Cronos could now analyze the abilities of a bio-boosted human in a contained environment. Lisker was placed into a combat demonstration against fifteen Zoanoids and he easily managed to kill all of them in under 30 seconds. With his advanced combat training, Lisker had easily adapted to the abilities of the Guyver and deemed that he was now the only one capable of recovering the other Guyver.
Battle of the Guyvers
Lisker organised an operation to capture Sho Fukamachi and Tetsuro Segawa, two high-school students who were present during the D-59 Incident. The inspector was surprised to find that Sho had bonded with the Guyver and that even though he lacked any kind of training, he had demonstrated the ability to dispatch multiple Zoanoids with relative ease. Lisker then bio-boosted and informed Sho of the nature of the Guyver and demanded that he return to Cronos with him. Sho, of course, refused and the two bio-boosted humans fought.
Even though the armour units were the same, Lisker had the upper hand with his superior combat training. He demonstrated keen tactics and precision of movement, defence and offence whereas Sho fought clumsily by comparison. However, Sho proved that inexperienced fighters could master the abilities of the Guyver in the heat of combat, as he demonstrated when he made first use of his high-frequency swords and got a lucky hit on Lisker's faceplate. Lisker wasn't about to stand for that and retaliated fiercely, but before he could land a killing blow, his control medal began to surge and malfunction. Lisker doubled over in pain, allowing Sho to end the battle with a swift blow to the head that knocked out Lisker's control medal. Without the medal, Lisker's Guyver symbiote overloaded and began to devour its host. As Lisker staggered around melting, Sho put an end to his suffering by unleashing the Mega-Smasher, vaporising Lisker completely.
Lisker was brash, arrogant and condescending. He held a significant level of authority within Cronos which only served to inflate his ego further. His egomania only increased after he bonded with the Guyver and he believed himself to be a warrior superior to all others, even Cronos' Hyper-Zoanoids. This arrogance, along with his damaged Guyver unit, led to his demise.
Since the unit he bonded with was damaged, Lisker's Guyver form appeared to suffer some slight disfigurement compared to Guyver-I. The faceplate seemed to be scarred on one side and the helmet's breathing vents were both on one side with the Sonic Buster emitters on the other side. The control medal had a noticeable dent in it and would surge if Lisker overexerted himself in combat. Despite the damaged state of his Guyver unit, Lisker still gained all of the Guyver's standard weapons. In the manga and OVA, he did not have the opportunity to demonstrate his full array of powers, but in the 2005 anime he was shown to be capable of using the Guyver's high-frequency blades, head laser, Pressure Cannon and even the Mega-Smasher.