In the PPC itself, Cornelius manifests himself as a light green hologram whenever he needs to interact with someone face-to-face. His specific avatar is that of a young bald man in a turtleneck and slacks. When his presence is required on a mission, Cornelius is able to use an experimental DORKS and a mobile emitter to create any form for himself. This form is unstable, however, due to the mixing of different canonical technologies, and can only be maintained for a short time.
Not much is specifically known about Cornelius's background except that he was apparently rescued from a Halo badfic by members of the DMS in early 2009 HST. Upon his induction he was transferred into the DIAU.
In mid-September 2010 HST, Laura Dukes and Danny Richardson were temporarily assigned to work in the DIAU as punishment for prematurely ending a mission. Cornelius was assigned to be their supervisor. This arrangement lasted until November 2010. At a later date, Rachel Calendar, formerly an intern working under the DMS, was assigned as his partner.
Cornelius was one of the founders of the Observatory, and is known to frequently send his main avatar into it to monitor the myriad time streams of the multiverse in addition to keeping track of the DIAU's agents.
Being an AI, Cornelius is constantly hooked up into the PPC computer system and is thus able to field incoming missions and messages with ease. In the field, he is able to monitor dangerous situations and inform agents of the potential risks they run with any particular plan. He has refused to have a CAD integrated into his programming due to the risk of neural failure.
Cornelius is well aware of the negative image AIs have received in popular fiction and so tries his best to put people at ease with a friendly and charming attitude. This is not a fully realized approach, as he always refers to people by their title and last name ("Agent Dukes," for example). He likes to learn about people and will sometimes ask personal questions of the agents he works with in order to further his knowledge.
Some of the agents who have worked with him are suspicious of his actions and motives, pointing to a few instances where they claim his instability can be seen. The Flowers have dismissed all of these claims as purely speculative.
It should be noted that AIs originating from the Haloverse come in two varieties: "dumb" AIs, which are actually quite brilliant in their given fields of expertise but quite limited in anything else; and "smart" AIs, which can easily adapt and learn but pay for this versatility with a limited life span of seven years (barring any occupational stress that might shorten said life span). After that point, the AI will either effectively think itself to death or go rampant, a state in the Halo universe where AIs may exhibit the typical mad AI mindset.
Cornelius is a "smart" AI. As of September 2013 HST, he has an estimated two years of operational life remaining.
Partnered with Danny and Laura
- "Buy Victory Bonds!" (Kingdom Hearts)
- Laura, Danny, and Cornelius land in the middle of a wartime romance between Vexen and Marluxia.
- "A Failing Grade" (Kingdom Hearts)
- It's back to school for the DIAU crew as they try to save three Organization XIII members from a gang of Sues.
- "We Were Sailing Along..." (Kingdom Hearts)
- An Axel!Sue (yes, Sue) is by far the least horrifying thing Laura and Danny are forced to face during their last mission with Cornelius and the DIAU.
Partnered with Rachel
- "FNGs and Vets"
- Cornelius is seen working in the Observatory and interacting with his new partner.