obsessive: Hap's whole life revolves around his research. His entire home is dedicated to it, as is every waking moment. In fact, he deems sleep "a waste of time, but necessary" and only accomplishes it with sleeping pills. Every one of his doors is keypad locked and every room, upstairs and downstairs, monitored by camera to protect his research. When away from home, he keeps an eye on these feeds on his laptop and controls them remotely if necessary. He appears to have no relationships besides those with his subjects and his mentor (who conducts similar experiments of his own). Hap fixates on individuals that can further his research, none more so than Prairie. Making her his partner becomes a close secondary obsession, driven by her unique metaphysical insights and the bond he imagines that creates between them.
meticulous: Hap's study has been refined to perfection. He "built his lab himself" underground, soundproofed and fed by a natural spring. Adjoining glass cells allow captives social interaction to manage their mental states. Lighting changes and food is dispensed on a timed system, taking menial tasks off Hap's shoulders and minimizing his contact with the subjects. When it comes time to retrieve them for experiments, he sedates them with a scopolamine-like gas that puts them in an extremely suggestible state. On top of preventing physical struggle, it spares them psychological trauma by obviating memories of their death and resuscitation. Hap is also a capable engineer; besides the equipment used in the study, he invents medical technology to fund his research through the sale of patents.
detached: Hap considers himself a scientist, first and foremost. Empirical proof of life beyond death will revolutionize not only science but the world, though Hap doubts he will achieve it in his lifetime and seems content to have lain the foundation for the next generation of researchers. He whitewashes the inherent cruelty of the experiment by minimally interfacing with the subjects and focusing on the data. Hap believes he's removed his ego from the equation, a fundamental self-deception considering the chasm-steep power imbalance between him and his captives.
petty: Hap nevertheless has flashes of pure vindictiveness. These revolve around Prairie, who denies him her acceptance and willful collaboration. Homer is a subject with whom Prairie shares a genuine bond. Hap coerces him into seducing a new subject, Renata, and patches the sound of their intercourse over the lab's PA to devastate Prairie. When another subject, Scott, reveals Prairie has been lying to Hap, he's so blinded by rage he accidentally kills Scott, then takes his body back to the others and blames his death on Prairie. Lastly, when Homer and Prairie are able to physically touch for the first time, Hap drags her away, drugs her, and drives her out to the middle of a mountain highway. There, while pinning her down and holding a knife to her throat, he berates her, tears the strap of her dress, and then abandons her -- not only on the side of the road, but in that universe, as he leaves it and takes her friends with him.
lonely: Hap's most exploitable weakness is his loneliness and his reluctance to acknowledge it. The significance of two brief but potent interactions is all it takes for him to offer Prairie the position of his housekeeper. Though she's still very much his prisoner, Hap treats the arrangement as more and more normal as the months go on. At one point, his guiding touch lingers on her hand; at another, he asks if she's doing her hair different and remarks that it looks nice, with the ease and familiarity of a friend or partner. Even after that arrangement ends sourly, he tells her that, unlike the other subjects, he thinks of her as a partner in his research. Prairie notes that Hap, unlike the captives who have each other, has nobody except his mentor Leon. When Leon violently attempts to seize Hap's research, Hap is forced to kill him. Noticeably shaken, this prompts him to invite Prairie (now known as OA) to run away with him and continue the work together elsewhere. Her staunch disinterest further destabilizes him.
manipulative: Hap is aware that his behavior is unethical, or he wouldn't go to such lengths to cover his tracks or feel the need to obfuscate it to attract new subjects. He's adept at recruiting them with promises of remuneration and a sense of purpose. He charms Prairie, who has been sheltered and medicated all her life, into feeling special and seen. When an approach fails, like his offer to fly Renata out of Cuba, he uses what he's learned of his target and changes tack: forcing Homer to get her alone and seduce her. In the midst of this, Homer flees the hotel to escape Hap. However, Hap catches up with him and gaslights him about his chances of getting any justice in a foreign country.
personality.