Background
Hank is primarily an HK-24 "Hunter-Killer" droid constructed during the Old Republic era. His own history is largely unknown to him, but he believes he was inactive for several thousand years total, with at least three distinct periods of activity. He's been modified and reprogrammed at least twice, which resulted in significant loss of memory surrounding his origins.
The history of his model and rare slivers of memory suggest that he was part of a private combat force perhaps ten thousand years ago. He has vague memories, which he presumes were at least two thousand years ago, of serving as a bodyguard, less directly aggressive and militant, and barely civilized.
Most recently, approximately one-hundred fifty years ago, he was a companion, and perhaps even friend, to some sort of reclusive philosopher, a Dathomiri who called herself Rose. His name was given to him by Rose, a friendlier name derived from his model, HK-24. Though he doesn't recall ever seeing his companion use the force, the moral and philosophical lessons he learned from her suggest that she was likely a Jedi. Though some memories are vague, Hank believes that he deactivated himself while grieving Rose's natural death.
Within the last year, he was discovered by a team of anthropologists exploring Dathomir. He was subsequently restored and reactivated by engineers loyal to the Rebellion. Since his reawakening, he's spent most of his time learning to interact with people and trying to uncover his past.
Motivation
At the core of his personality is a desire for justice. Certainly a result of his time with Rose, Hank has a fierce belief that every being has a right to its own destiny. Largely this manifests itself through a tendency to defend those who cannot defend themselves. He does not hesitate to step in where he believes help is needed. His dedication to justice does not, however, prevent him from aggression. Though he may often seek peaceful resolution to conflict, he can be quick to accept that his foes have chosen their destiny, to die painfully and without his mercy.
His primary purpose is clear to him, continuing the beliefs given to him by Rose. Separately, he has an underlying curiosity about his life, wanting somehow to understand who he is within the context of the previous ten thousand years. He will seek, from time to time, additional knowledge about himself. In free time, he reads historical texts covering the Old Republic era. He dabbles in a rough droid equivalent of geneaology, trying to track manufacturing information and ownership registries back through millenia.
Beyond his duty, he finds most of his happiness through companionship. Before Rose, he had only rudimentary emotions, and never felt alone. During his time with the Dathomiri philosopher, he only saw her, and until her death, never felt the pain of solitude. Now that he's back among society, with a complete personality, he finds great comfort and peace just being around others, mostly listening and observing. He is loyal and protective of his friends.
Duties
Hank has 2 points of conflicted relationship with the Mandalorian Crusade. They admire the efficiency of the HK series of droids, but even after thousands of years, the 24 model invokes memories of betrayal. Neither Hank or any Mandalorians he encounters will know if he participated in opposition to them, but maybe it's best not to take chances.
Additionally, 1 point of conflicted relationship with the Jensaari. They recognize Hank's potential value as a living time capsule, filling in any gaps in their memory of historical events. However, since I don't seem to have much of my memory, they're simultaneously offended by some apparent disrespect towards "memory", and somewhat fearful that I represent an unaccounted for vector through time, potentially bringing old values into the present.
Description
Though his mechanical origins suggest that he was initially nothing more than a weapon, each subsequent active phase of his long life brought him closer to humanity. He now has a full range of emotions, and his voice is expressive and human-like.
Wrapping his droid body, from ankle to wrist to collar, is a woven fabric that somewhat fleshes him out. Primarily, though, it ensures that clothing doesn't get caught in his joints. He wears clothing as somewhat of an affectation, primarily to make others around him more comfortable regarding him as one of them, rather than a simple droid. His hands, feet, and head remain exposed and robotic, though he occasionally wears a custom helmet that belies the actual shape of his head.
His face naturally looks menacing, part of the design of the HK series of droids. To counter this, he has painted light blue circles around his eyes, and installed similarly colored lighting for his optical sensors. The implied larger eyes and comforting hue make him far more approachable. The original orange optical lighting remains, though it's rarely activated and only towards expressive great anger.