Tarasha Euten

The lady herself, with her charge.

"'As the little emperor he pretends to be, he does so chronicle himself. I have heard of you. Tarasha Euten, Chamberlain Principal, and to all intents a mother to him. A mother.' Curze sighed. 'Thanks to the genius of my father, my kind does not enjoy the luxury of mothers. You are rare. You are a rare and obscene thing, you ragged witch. I wish Roboute had been alive to suffer the damage of your death.'

Euten rose to her full height and looked the monster in the eye. 'Go to hell, you bastard,' she said."

– Tarasha Euten, being the absolute baddest of asses.

Tarasha Euten, also known as Guillimom, was one of Konor Guilliman's chief retainers during his time as Consul of Macragge, and continued to serve Roboute Guilliman as he became Lord of Ultramar and then Primarch of the Ultramarines. She is notable for being the only known mother figure any of the primarchs ever had (leaving aside the careless deadbeat Sphess Karen), who is not a literal Bitch, and is therefore awesome, since this means that she managed to raise a Primarch without them going nuts or causing him irreparable psychological harm. An interesting little note is that sadly, the Lion very nearly also could've had this experience as well, as apparently Luther's wife and daughter died shortly before the discovery of the first primarch. Some interesting food for thought. Vulkan meanwhile was raised by a single father, N'bel, who did an equally well job by him.

Early History

As a young woman, Tarasha served as seneschal to Consul Konor Guilliman. The two were personally close, though whether their relationship was more than platonic is unclear. When a strange pod crashed into a forest on Macragge, the nobles who found it brought its contents--an infant surrounded by a glowing aura--to Konor, who adopted the child and named him Roboute. Tarasha helped raise the boy, watching as he grew rapidly into a military genius, brilliant scholar, and wise leader. Perhaps her proudest moment as his adoptive mother was his peaceful resolution of a rebellion among the tribespeople of the Illyrian Mountains; rather than crushing the Illyrians, he had instead presented their chieftain with a sacred artifact which the consuls of Macragge had stolen generations before, causing the Illyrian chieftain to end his campaign and resolve to become a wise and just leader in Roboute's mold. It was at this moment that Tarasha knew he was ready to become a true leader and king of Macragge.

After Konor's assassination and Roboute's ascension to the office of consul, he kept Tarasha on as his seneschal and chamberlain. When the Emperor arrived at Macragge, Guilliman left her to govern the planet in his stead while he went out to help his father unite the galaxy under the aegis of the Imperium. Guilliman also made sure to secure regular Rejuvenat treatments for her, meaning that she would have a much longer lifespan than a typical human.

Horus Heresy

When Guilliman retreated to Macragge in the aftermath of the Battle of Calth and began laying the foundations of his "Imperium 2.0" backup plan, he often turned to Tarasha for advice. Though she was now elderly, she had lost none of her fiery, boisterous spirit, and continued to speak to the Primarch as if he were the same child she'd raised to manhood. She still referred to him as "boy", a form of address unthinkable to anyone else in the galaxy, while Guilliman called her "mam" and treated her with great respect and affection, frequently confiding in her about his doubts and fears. In turn, Tarasha was one of the few who could accept and verbalize that Guilliman was not infallible, and sought to remind him of that fact. She was also not above sassing him, as proven when he spent a night getting drunk with his Space Wolves watch pack and she told him off for it the following morning.

Her finest moment, however, came when Konrad Curze invaded the Fortress of Hera. After wreaking havoc and (apparently) assassinating Guilliman and Lion El'Jonson, Curze made his way to Tarasha's quarters, killing her personal aide and demolishing the Space Wolves when they tried to intervene before threatening Tarasha herself. Notably, Curze actually seemed kind of jealous of her relationship with Guilliman, which leads one to wonder how well Space Marine Batman Who Laughs might have done if he'd had a mother of his own (or, you know, any positive influence in his childhood). Despite her sheer terror at being confronted by the Night Haunter himself, Tarasha steeled herself and told him to fuck off, which cements her as one of the bravest people in all of 40K. She was saved at the last moment by Vulkan, freshly resurrected after having burned up in Macragge's atmosphere and out for Konrad's blood. Later on, Tarasha was present when it was revealed that Guilliman and the Lion had survived Curze's attack thanks to the Pharos, which had sensed Barabas Dantioch and Alexis Polux's desperation to save the loyal Primarchs and allowed them to pull the two through to Sotha. When Guilliman learned that Curze had attacked Tarasha, he immediately stepped back through the portal without even noticing, because he was that worried about his mom.

Post-Heresy

It is unclear what happened to Tarasha after the end of the Heresy. One audio drama puts her aboard Macragge's Honour while it's under attack by Chaos forces, during which she tells an Ultramarines sergeant about Guilliman's pacification of the Illyrians while they're slowly dying from smoke inhalation. By the timeline this would have had to occur after Guilliman's ship returned from its grudge match with the Infidus Imperator, which would mean Tarasha was old as dirt by the time this happened.

She is of course very probably quite dead baring exceptionally unlikely warp time shenanigans (a story where Guilliman gets his mom back would be kino) by the beginning of the 42nd Millennium, but Guilliman still misses her and wishes he had her counsel. And, really, who wouldn't want their mom when they'd woken up after ten millennia to find out that the galaxy was worse than ever and their dad's Imperium of Reason and Enlightenment had collapsed into a superstitious, oppressive, theocratic nightmare?