Eula and Amber are both part of the Knights of Favonius. Eula is the Captain of the Knights of Favonius Reconnaissance Company and Amber is an Outrider of the Knights.
Eula, due to her family, is not really appreciated by other people in Mondstadt. She is a descendant of the once-aristocratic Lawrence Clan, also known to be Mondstadt's oppressors during one of the darkest periods of the city's history. Amber always sees the best in people, so the same goes for Eula. Amber is one of the few who really understand Eula for who she is. Amber even helped Eula in her debut in the Knights, by cleaning her room, showing her around, or helping her with simple tasks. In fact, Amber is extremely kind to Eula.
They each have a voice line about each other. Amber's talks about how great Eula really is and how misunderstood she is as well. She mentions that Eula is a great friend of hers, and that her sense of humor may be a little odd but is fine once you get used to it. Then she wonders how she can get other people to see Eula for who she really is.
Eula's voice line about Amber comes of as a more "tsundere" type, with her talking about how Amber helped her with an array of things when she first joined the Knights. Because of this, "she must pay!".
Eula's short vision story talks a bit about how she was mentored by "a long-forgotten old Outrider", which is believed to be Amber's grandfather.
Eula's third character story focuses entirely on Amber. It starts off by talking about how Mondstadt is the city of freedom, and if "there is one person among the Mondstadt masses that Eula can trust, it is Outrider Amber". How everyone loves Amber, so when the Outrider is around, people will be more friendly to Eula and shopkeepers will sell their wares for a cheaper price; sometimes even exchange a few words with Eula which causes the knight in turn to show a more agreeable side.
Because of all this, and Amber's kindness, Amber will accompany Eula on trips out, run errands for her, or deliver goods straight to her home. Amber is also the main reason why the Mondstadt citizens hear all about the long list of achievements Eula accomplishes on her missions, making sure to brag about the Spindrift Knight to all the cityfolk.
"Early one weekend morning, Amber stood behind a makeshift rostrum erected on a wooden crate and began announcing Eula's latest highlights". From a combined effort of Amber's work for her friend and Eula's impressive work, Eula's life began to change noticeably over the years. Many people are no longer as aggressive towards her, including other knights who are impressed with her consistently outstanding work. For the members of the Reconnaissance Company, they follow Eula loyally and support her unconditionally.
Over everyone else, though, the person who supports Eula the most and tirelessly roots for her, who is now also the most delighted to see the change in attitudes towards Eula, is Amber. "They had been friends for a long time before Eula ever joined the Knights of Favonius, and as the granddaughter and beloved mentee of the first Outrider, Eula trusts her completely."
Eula's specialty food is the Moon Pie, and in Amber's voice line "Amber's Troubles", she says " Oh... Do you have any idea how to make a decent Moon Pie?". This could be interpreted as Amber wanting to make Eula's specialty food for her.
In Eula's story quest, the Traveler talks to Amber about a member of Lawrence Clan, Schubert Lawrence, after Amber wanted to help them. After that Amber tells the Traveler a bit about the Lawrence Clan. She mentions that they tend to be a bit difficult to deal with. Nevertheless, she praises Eula and defends her, saying that Eula is her buddy, that she's special and portraying her too. Amber goes on to boast a bit about Eula, saying that she has her own beliefs, and that it shows. She then says that Eula is very easy to get along with, before redirecting the traveler to her for their task.
Later on, when the Traveler meets with Eula, they mention that Amber told them to go seek out Eula. Upon hearing this, Eula agrees to help out the Traveler, saying "Besides, if it's the Acting Grand Master's assignment, and Amber's the one who recommended me, I should comply". In this case, she uses Amber's name instead of "Outrider", which shows familiarity.
After the trials in Dragonspine, Eula and the Traveler go back to Mondstadt and head to Good Hunter, where Amber is standing. Amber greets them, saying "Oh, hey Eula! I see you've met the Honarary Knight!". Paimon greets her back, and then Amber invites them all to sit down to eat together. Eula smiles and replies "Very well. It's been some time since we've last shared a meal together". As they talk, Amber mentions that Eula once treated her to Schubert's favorite dish, yet the pyro girl couldn't finish a bite because of the sour taste. Eula responds by saying that she never expected for the two of them to have completely different tastes in food, and then says that if she weren't in such a good mood then that alone would be reason for her vengeance.
At this point, the Traveler says "Huh, so even Amber doesn't escape your vengeance?". Eula responds by saying that it's hard to find someone in Mondstadt who "attracts as much contempt as she does". Cheerfully, Amber says "Haha, it's fine when you're joking between us, but I'm afraid our Honorary Knight might misunderstand you". Amber then tells the Traveler that Eula is always talking about vengeance, but that's just how she is and they shouldn't take it too seriously. Eula stubbornly replies that she is serious and will remember every transgression committed against her. After the meal, Amber says she'll pay the bill, to which Eula mentions that she already left Mora under the plate to account for the extra salad received.
Shadows Amidst Snowstorms
In this event, Amber invited Eula to Dragonspine to help the Adventurer's Guild who's hosting an event to help his members train in ideal and safe circumstances, and also to built a snowman with a kid called Joel. Amber decided to play further with Joel while Eula helped an adventurer.
After the Traveler left, Eula come to confront Albedo about what he did to Joel, or what an imposter did. During this time, Amber was searching Eula screaming her name out loud. When Amber joins them, Eula starts to lie to her, saying that "there have been a few minor incidents. But nothing I haven't already dealt with" to not involve her. Then, they head back to the camp with Bennett.
In Act 2, while discussing with Albedo, the Traveler heard noises of falling stones. It was Amber, Bennett and Eula. Because of Bennett's bad luck, they haven't made it to the base camp yet. After seeing another time of Bennett's bad luck, Eula said to Amber, "Amber, if you are ever required to partner with Bennett in your future work and you encounter anything like this again, do not make any rash action. Wait for me and I will come to support you." Amber replied in a confused manner that yes of course. Then, Amber tells she feels tired, so Albedo propose to take a rest in his camp. Hearing Amber saying she's sleepy again, Eula says "Amber will fall asleep in the snow if we keep going much longer... Come on, let's move!"
In Albedo's camp, while Albedo prepares dinner, if you decide to talk to Eula about the snowman, she says that Amber said the snowman she made was too artistic, and the conventional style was more rotund in apparence, and Eula couldn't tell if she was complimenting or mocking her. If you ask her how she is holding up, she replied that we should talk to Amber and Bennett since they're not as well acquainted with Dragonspine as she is. If you decide to talk to Amber about what happened today, she compliments Eula by "Eula is a good person. She might not show it, but she'd never let that kind of stuff get to her".
While eating, Bennett falls asleep and mentions Sticky Honey Roast. Eula looks at Amber, saying, "Sticky Honey Roast... That's you favorite, isn't it, Amber?" and Amber confirms it. Then Amber says that she used to take Eula to Good Hunter a lot back when they first met. Since they always took the same thing everytime, Sara would start cooking their usual orders as soon as she saw them coming. When Amber finished her anecdote, Eula clears her throat, and after Paimon said "Aw, it's nice that you two are so close." Eula denied it by raising her chin up and putting her hands on her hips, and says that two people simply sharing a meals says nothing about the relationship between them. Albedo argues that it depends if it's a one-off meal or a regular occurence. Paimon noticed her comportement and tells that she does that whenever Eula doesn't want to admit something. Amber already knew this and didn't know Eula's tells were so easy to spot. Eula got annoyed, stood up and asked if she's free to go.
After saying that she have a frozen lake she needs to be at, Amber stood up too worried about going for an ice bath at this time of the night and tells Eula to not go without her. Eula thought she wanted to get some sleep, but Amber argues by "No, I should come with you. It's late and it's dark, and you're not good with directions like I am. Come on let's go together". Then, they left.
The next day, while they were heading back to the adventurer's camp, a stone falls alerting them to an avalanche. Eula grabs Amber and and covers her with herself to protect her from the falling rocks. Since Bennett and Albedo fell during the avalanche, they all go down to rescue them. After finding the two of them, there’s something bothering Eula and the Traveler. When Amber said that she didn't think she had spent so much time on Dragonspine before, and even it's cold the view is amazing, when she asks Eula about it, she didn't responded, lost in her thoughts. Eula requested Amber to repeat again, and Amber said "whenever I've met with you at Dragonspine in the past, we always stick to the same few spots" and that it's so much more vast and beautiful than she realized. Though Eula still seemed distracted, she agrees.
Everyone follows Albedo onward, and Eula interrupted the hiking because Amber and Bennett didn't look well, asking for a break. Eula noticed that Amber hit her head earlier, and embarrassed, Amber asks if she's sure it's worth holding everyone up over a little thing like this. While resting, Bennett, Amber and Eula talked. When Eula said to get some rest, Amber giggles and says "Eula might come off as a little frosty, but she takes caring for her friends super seriously, more than anyone else I know. Everytime I see that look on her face, I'm just like-". Then Eula angrily staring at Amber, who begs her to stop staring at her.
Suddently, "Albedo" attacks Eula and the Traveler. They all fight back, and at some point, an Albedo stabs the other. It was indeed the imposter who got stab. Then the impostor became a fellflower, a huge whoopperflower they have to fight. When the fight is over, Amber asks what's going on since she doesn't understand. Returning to the camp, the first thing Eula asks if Amber is feeling better, worrying for her. She expresses that this has been quite an eventful day, and Amber agrees adding that she is really tired now. Then, they leave needing some rest. After the act ended, you can find Eula and Amber with Joel near the snowman.
In her trailer, Eula: Flickering Candlelight, Eula pauses dancing to ask Amber "Are you here to spy on me?" (direct translation: "How long are you going to spy on me for?"). After being caught, Amber said that she was just looking for Eula because she worried about her. Eula then proposed to Amber to dance tango with her. In the direct translation, she says "Have a dance with the sinner", while in the translated version she says "It takes two to tango". Flustered, Amber replies with a confused "Huh?" as the trailer ends.
On Genshin Impact's twitter (Japanese ver.), there is a trailer showing the upcoming features of the Serenitea Pot, where you can place playable characters inside. In the house, Eula and Amber were placed next to each other, talking with one another near the front.
In the Version 2.3 "Shadows Amidst Snowstorms" trailer, Amber and Joel built a snowman in Dragonspine with Eula watching, worring about something. Later on, they fight along with Bennett against "Albedo". Also in the related soundtrack "Genshin Impact EP - Gentle Waves of Frost", at the end of the second sound "The Horizon" we can see Eula and Amber going towards the mountain to the place where the event begins.
- “Eula is a great friend of mine! You just need to get used to her sense of humor and you'll get along fine! The only reason she's misunderstood by so many people is her family name. How can I get them to see her for who she really is?”
- — Amber's voice line about Eula
- “Amber's someone who thinks for herself. On the day I first joined the Knights, she cleaned my dormitory and gave me a tour of the headquarters, and she's helped me with a myriad of other things in the time since. Now, everyone looks at me like the older sibling to do everything for them! Hmph. For this, she must pay!”
- — Eula's voice line about Amber
- Eula – “Are you here to spy on me?”
- Amber – “No... I was just worried you might be in trouble...”
- Eula – “Not yet... It takes two to tango. Shall we?”
- Amber – “Huh!?”
- — Eula's Character Teaser, Eula: Flickering Candlelight
- “However, there is one exception among the Lawrence Clan. My good buddy — Eula! [...] Eula is special! She's not quite like the other members of her clan. She has her own belief and it shows. In other words, she doesn't really adhere to the strict rules and conventions of her family. However, she's still quite knowledgeable about dealing with the Lawrence. I'm sure you'll see what I mean if you meet her”
- — Amber in Eula's story quest
- Amber – “This is Eula, the Spindrift Knight and Captain of the Knights of Favonius Reconnaissance Company...”
- Eula – “Amber, you're being far too formal. The child is never going to remember all that.”
- — Amber introducing Eula to Joel
- Paimon – “Always eating together... Aw, it's nice that you two are so close. (Traveler) and Paimon always eat together, too. It's a sure sign of true friendship!”
- Eula – “Two people simply sharing a meal says nothing either way about the relationship between them.”
- — Paimon talking about Amber and Eula
- Eula – “We are done here, yes? I am free to go, am I not? Then please excuse me. I have a frozen lake I need to be at.”
- Amber – “You're going for an ice bath at this time of the night? W—Wait up, don't go without me!”
- Eula – “I thought you wanted to get some sleep? So maybe you should stay here and rest.”
- Amber – “No, I should come with you. It's late, and it's dark, and you're not good with directions like I am. Come on, let's go together.”
- — Amber asking Eula to go join with her in an ice bath
- “Eula might come off as a little frosty, but she takes caring for her friends super seriously, more than anyone else I know. Every time I see that look on her face, I'm just like... Aah! Stop staring at me!”
- — Amber talking about Eula
The ship instantly became popular as soon as people saw the interaction between Amber and Eula in the latter's demo trailer, making the ship's growth one of the fastest in Genshin's shipping history. The way Amber was fascinated by Eula's moves and then visibly scared when Eula invited her to dance, or how Eula knew in advance about her spying and invited her to dance in a rather seductive manner, has often been interpreted as the possibility of a romantic tension between them. For example, one of the viewers jokingly called the video of this scene in different languages as "Amber's gay panic in different languages".
Due to this, their dance has become the dominant theme in the fan art dedicated to this pairing. Fans of the ship also often like to combine the two girls as a Pyro-Cryo combo in their teams, also noting that this combination is well emphasized by the contrast of red and blue in their appearance.
Eula's story quest only made this ship deeper, as it also paid attention to the relationship of the two girls and it was found out that they have been good friends for a long time. Eula's tsunderness, or the fact that Amber seems to be actually the only resident of the city who fully respects and trusts Eula, only added fuel to the ship. Especially with Eula returning the trust, mentioning that she trusts Eula completely, and considering how skeptical and untrusting of others Eula is, it means a lot for her to place her entire trust in someone.
Since shipping with Amber mainly included ships with characters that had much more popular ships with other characters, and Eula appeared only recently and most of all interacted with Amber, this ship easily became, if not the most, then one of the most popular for both characters. While not everyone shares the interpretation of the romantic potential of this pairing, many people still tend to agree that this ship looks cute and stands out from others.
- In the description of the Snowman Head: Huff-and-Puff of Shadows Amidst Snowstorms, it says that Amber used the expression of Eula to make this kind of snowman head ("It is said that the very first snowman of this kind was built by an Outrider who used her good friend's default expression as reference. Her friend's response to this flattering imitation? Laughter. Surprising laughter.")