Hafteon-Mar

Freed during the Psygonauts escape from the Ilocanos-7 shipyards, Hafteon-Mar is a freak accident once a proud hunter now a half Aeonite/half stag "thing" unable to die from any injury.

Hafteon was cursed by Artemis to become a Thermesian Stag, experimented on by the Collective, and possesses spotty memories and an unusual connection to the Cosmic Aurora similar to AJM-001 & Ulysses "Ollie" Dylos (person). The Psygonauts' second-in-command convinces AJM-001 to keep this dumb, boisterous & pervy meathead around in the hopes of figuring out the mysteries around AJ's memory loss and Dylos' connection to the Cosmic Aurora.

Origins:

While details of his early childhood are completely gone, Hafteon was a novice in the Thermetolian Hunters Guild with the goal of winning favor from Artemis so much so that he could request to see her naked. 

While the guild would've kicked Hafteon for even mentioning such a thing about the vengeful goddess of the hunt. Membership was low, the boom in the Thermesian Stag population needed to be culled & Hafteon was a protege (passing his initiation for his athletic prowess, unusually acute senses, impeccable marksmanship).

During one of their hunts, Hafteon tracked the biggest stag he'd ever seen. Labeled as a breeding stag for next season's stock, based on the Artemesian Index, the senior guild members told Hafteon to let it go. However, Hafteon wouldn't listen.

Tracking it to a nearby stream, Hafteon waited for his shot when the stag walked through the trees and towards Artemis and her nymphs bathing in a stream. Giddy at the chance to impress the naked goddess, he dropped the stag with a single bolt.

Breaking through the trees, Hafteon found the goddess of the hunt and the spring they were bathing in covered in the stag's blood. Furious, Artemis cursed Hafteon.

Terrified, Hafteon ran through the forest to find his guild when he started changing into a deer. Just then, the guild's Epirastiff hunting dogs caught his scent.

The next thing he remembers is waking up on a sterilized operating table as a half-aeonite/half-stag freak. During the Ilocanos-7 shipyard escape, Hafteon discovered he couldn't be killed and was able to overcome Delot security and snuck onboard without anyone noticing (since no one would transport a cursed Hellecian, denoted by a "-mar" suffix).

The only reason the Psygonauts found him at all was because he slipped up while watching Atanica from the ventilation ducts.

Aboard the Psygorellius:

Discovering his unkillable nature was a result of his unusual connection to the Cosmic Aurora, Dylos convinces AJ to keep him onboard so they can study him and maybe figure out how what caused their own conditions. 

While aboard the Psygorellius, Hafteon is the firing range instructor and the hunt master responsible for scavenging food on savage/uncultivated worlds. Given his unkillable body and ability to get into places unseen, Hafteon-Mar can sneak into places and spring captured crew members. While also being used as a meat shield for intense firefights and the litmus test if an environment or substance will kill a crew member.

While Hafteon is rather bull-headed in his attempts at wooing Atanica. It's more about being socially anxious around women than being a pig (hence why he chose hunting as a career). However, it was his lack of respect for Artemis' boundaries that turned him into a stag. 

Over time, Hafteon learns to respect boundaries and how to earn his way into a woman's heart.

And even if Atanica may not be romantically interested in Hafteon (as a half-stag). She learns to respect (even value) his talents on mission. While also teaching him how to be less of a beast and more of a man.

However, Syracilus' tests prove Dylos was correct and that everything Hafteon has become was no accident.