Hephaestus
Hephaestus Blood Code- Rin Murasame "A blood code received from Murasame. It holds her passionate will to support allies who throw themselves into difficult battles and watch over them with a smile when they come home. This code focuses specalizes in dexterity based weapons and uses devious Gifts to toy with the enemy."
Introduction to Blood Codes and Rin
Blood Codes are the abilities imbued within a Revenant's Blood. Each Blood Code is unique to each Revenant that resides within the Gaol of the Mist. Once a Revenant has awakened from their slumber after the BOR parasite has been placed in them, the blood takes on a Code which I believe derives from the characteristics of that Revenant.
I'd like to think Rin is either a first/second generation revenant. She's burdened by the decisions she's made in the past that made her reluctant to battle. She replaced her unwillingness to go to the front lines by handling the support side for everyone at Home Base and always exudes a cheerful personality for the crew to come home to.
Greek Mythology
Rin's blood code is based on the Greek God Hephaestus.
Hephaestus is a Blacksmith and a fire God known for his creations of many different things. Hephaestus was notably a secondary God in various mythologies and the only pertaining role he did have was his revenge against his mother Hera, who claimed to have hated him, called him ugly & deformed after birth. He was tossed away from Hera but the gods Thetis and Eurynome rescued him.
As for the revenge against Hera, he created a golden throne and Hera was so enthralled by the creation that she immediately wanted it for herself. The minute she sat on it, she was trapped by invisible cords that refuse to let her go free. Hephaestus was the only one that could see these cords and the other gods begged Hephaestus to let Hera free but he refused until he got drunk by Dionysus, the god of wine and vegetation.
Hephaestus is also famously known for being the creator of Pandora, after being commanded by Zeus. Pandora was created after inducing Prometheus' punishment for stealing Hephaestus fire from his workshop.
Similarities between Rin and Hephaestus
Hephaestus was known for his creations in his workshop. He provided armour and weapons to many famous heroes and gods. Rin is relied on for handling maintenance, upgrades and selling new Blood Veils and weapons in her workshop.
Hermes, Davis' blood code is also a sibling of Hephaestus. Of course, we don't see them interact in the game even though their stations are right next to each other. Presumably, they both get along since I assume Davis also gets his weapons tuned by Rin.
Since Louis' blood code is Prometheus and Prometheus was the one who stole fire from Hephaestus' workshop along with the knowledge of metalwork, these Greek Gods only interacted indirectly through those instances. Louis and Rin do get along in the game and they both support each other while Rin looks forward to the reports from him, Louis trusts her with managing his weapon, bringing new material and other things relating to Rin's workshop.
Eva's blood code is Harmonia but the relationship between Harmonia and Hephaestus is completely different from Rin and Eva in the game. Hephaestus gifted Harmonia a necklace and the lore of Harmonia's story is called: Harmonia's necklace. The necklace caused great misfortune for Harmonia but it grants the wearer eternal youth. Hephaestus gave Harmonia the necklace out of spite of her mother Aphrodite who cheated on Hephaestus with Harmonia's father Ares. However, as we can see from cutscenes, Rin sincerely cares about Eva, especially when Eva left Home Base not knowing the depth of her condition and felt upset about not being able to keep a good eye on her.
Rin's has the blood code Hephaestus while Mia holds the blood code Artemis. These Greek god and goddesses are siblings, and while they don't interact much in Greek Mythology, it's understandable that Rin has taken a shine to Mia. Mia was able to fit in at Home base with Rin around and I think Rin is just as excited to have someone who is close to her age that she can befriend.
Hephaestus was known for his supposed 'deformity' but from how I'm seeing it, Rin doesn't have any physical deformity. She wears her purifier mask everywhere but we learn from the artbook that it's due to her handling weapons all the time. Working with BOR parasites and queen blood metals would probably emit some miasma or toxins in the air.
Then there's Rin's name in battle "Yaksha" or in other words demon. With Hephaestus' nature in Greek Mythology, the Yasksha part of Rin's background would relate to Hephaestus' spiteful nature against other gods that did him wrong. Rin doesn't exhibit Hephaestus' true nature but can easily reveal those characteristics during battle only. With Rin, she feels guilt with the things she was incapable of doing but Hephaestus' didn't deal with those kinds of emotions.
However, with the strong battle experience Rin displayed in her memories, she has that advantage over Hephaestus'. Hephaestus' as I have read, hasn't fully immersed himself into battle, he's more of a support for battle providing weapons, shields, and armory to the other gods (along with his knowledge of fire and metalwork). Rin in the past showed the opposite of that. While she is now gotten comfortable being in the support role and acquiring the knowledge and proficiency of helping other Revenants, she doesn't carry any grudges, unlike Hephaestus.
Hephaestus was more along the lines of deception with the mythology behind Harmonia's necklace, Pandora and the golden throne for Hera. We see those traits being exploited more within Rin's Gifts for her blood code. "Uses devious Gifts to toy with the enemy." Several of Hephaestus' creations were for deviousness and or weakness for the gods he gifted his creations. While there's not much connecting lore between Hephaestus and Rin, the one major common trait they share is that they're both seen with a hammer in their workshop.
Hephaestus' Gifts
Avance-Increases the amount of ichor gained from drain attacks. Pioneer's Guidance-Makes Gifts easier to master.
Hephaestus was always finding the best of ways to master and perfect his creations over all things, including the creation of Pandora. These two Gifts are from Hephaestus' subconsciously ingrained mindset to perfect his works. - Inhibit Resistance- Increases inhibit resistance. Inhibit Removal-Cures you and your partner of inhibit. Use to block the effect before being afflicted.
These inhibit preventative Gifts is based on Hephaestus' defiance against certain Gods. He would conjure up an invention or a certain craft that would end up leading to the other's downfall.
- Swift Destruction-Increases damage dealt in proportion to your mobility. Vanishing Hollow- Dodge attacks by transforming into mist. Countermeasure- For a limited time, dodging enemy attacks generates projectiles that attack the enemy. Evasive Snare-Dodging enemy attacks generates projectiles at the cost of ichor that attack the enemy.
These Gifts aren't as much related to Hephaestus since he didn't participate in battles. These correlate more towards the gimmicks of his creations. There's always an intriguing pro or con towards his creations such as the chair for Hera so these Gifts could translate from his creations rather than Hephaestus' power prowess. - Flames of Rage-Manipulates ichor to create a trap at your feet that immolates assailants. Dancing Blaze-Fires a ricocheting bullet. These Gifts related to Hephaestus' proficiency over Fire. He utilizes fire in his workshop for his creations or makes creations that would cause a cursed effect on it and the bearer of it which links to the Flames of Rage gift. Or the Flames of Rage could also reference Prometheus steals his fire.
Concluding Thoughts
Rin's Blood Code Hephaestus is aligned with her role at Home Base rather than the lore behind Hephaestus. She brings a lot of cheerfulness to the harsh world they live in. It makes sense why she doesn't fight anymore, but I hope there is some kind of development where she'll grow out of the fears of abandoning her comrades. I'm sure she'll play some sort of bigger role based on the true ending but for now, Rin deserves all the happiness in the world and I'm glad she was created differently from her Greek God counterpart.