Relationship between Keyleth and Vax'ildan

Keyleth and Vax'ildan met as fellow hired adventurers in the group that later became known as Vox Machina. Through their adventures, they became friends.

During their time in the Underdark, after having defeated Queen Ulara, Keyleth brought up her suspicions about Lady Kima of Vord and why she sought the Horn of Orcus that K'Varn possessed. As she went on with her arguments, Vax gleaned a deeper meaning from them, noticing something about her as she argued. When Clarota suggested that Vox Machina take Kima back to the surface, as they originally intended, due to the paladin's volatile personality, Vax objected, saying that it wasn't fair. He then told the druid that he knew about her hardships, that they all have had them, and that they have all made mistakes. Keyleth subsequently broke down in tears, wondering if they were doing the right thing and upset that she killed a lot of people. Vax, along with Percy and Tiberius, went on to mention that despite the situation in which they found themselves, miles underground, they were the only ones that could put a stop to K'Varn's plot, and that they would get through their ordeal together.

It was during their time in the Underdark that Vax began developing deeper feelings for Keyleth,   and over time, those feelings gradually became stronger. As for Keyleth, Vax's support of her and her moral outlook—as well as the commonality of their desires to remain true to their ideals—caused her to develop feelings for him. During their journey to Vasselheim, Vax insisted on helping her with scroll-making. During their "Trial of the Take", in order to infiltrate The Velvet Cabaret alongside Tiberius, Thorbir Falbek, and Kashaw Vesh, the five decided to adopt aliases. Vax took the pseudonym "Lord Scanlan Shorthalt of the Emon Shorthalts" and, as a suggestion to Keyleth, asked if she would be his "wife", which led to an awkward pause from everyone. Keyleth accepted the "proposal" and took the alias "Quaraline Shorthalt".

When it came time to travel to Pyrah for Keyleth's Aramente trial, Vax was in strong support of it. When Keyleth opened a portal into the Elemental Plane of Fire and dove in, despite his phobia of lava from nearly having his foot melted off, Vax conquered his fear and followed after her.

During his near-death experience when he first encountered the Briarwoods, as his life flashed before his eyes, Vax thought of Keyleth as being "beautiful, walking under the trees". Vax later finally revealed to the druid, after almost dying again at the hands of Professor Anders, that he was in love with her and emphasized it with a kiss. Vax's sudden display of affection greatly flustered Keyleth, and she later admitted to having some feelings for him as well, but she revealed that she was afraid of pursuing the relationship. Vax agreed to "wait for her", to give her the time she needed to make her choice as to whether or not she wanted him.

As their adventures continued and after the trauma of the Chroma Conclave's attacks across the world, Keyleth became increasingly receptive toward Vax's companionship, allowing him into her room the night before the party left Greyskull Keep, as well as kissing and hugging him after Grog's test of character against Earthbreaker Groon in Vasselheim.

After Vex'ahlia was killed and resurrected during their search for the Vestiges of the Divergence, Keyleth later explained that she was scared of losing Vax. While she thought she loved him, she felt too terrified to allow herself to explore that love because she feared outliving and losing everyone once she completes her Aramente.

Keyleth's views on the gods had led to further complications between them. In the middle of preparing for the battle with Umbrasyl in the city of Westruun, Vax apologized for leaving her side the night that Vex was resurrected. As for Keyleth, she later mentioned how uncomfortable she was about having to potentially depend on the gods for assistance. After Vax's "communion" with the Raven Queen in Vasselheim, Keyleth and Vax had a mild argument about whether or not Vax's ordeals over the past few weeks were fate or something that he really wanted and that it found him. And in the middle of their discussion, she told him that the Vax she knew was no different than the one that had undergone the communion, that the Raven Queen didn't need to make him special; he already was in her eyes. She did tell him, though, that she believed wholeheartedly that what he experienced was real and true.

Over time—and after receiving encouragement from her father Korren, Vex, and Pike—Keyleth realized that her earlier fears were ultimately unfounded, purely based on an unwritten future. She gained a new perspective on her concerns in the aftermath of finding Tiberius's body in the ruins of Draconia, with her dragonborn friend having been killed by Vorugal. Keyleth said her farewells to Tiberius and buried him. Upon returning to Whitestone, she eventually went to Vax's room and insisted on being with him for the night. As Vax poured his heart out to her and expressed his doubts about the two of them and where they stand, Keyleth interrupted, telling him about her conversation with Pike and the realization that they ultimately had "nothing to lose." Then she finally confessed that she loved him—and had for a long time—and apologized for taking so long to say it. Vax admitted again that he loved her as well, and they spent the night together.

After witnessing Keyleth nearly die in battle against Anna Ripley and her henchmen on the Isle of Glintshore, and after Raishan made her presence known to them in Whitestone, Vax voiced his fear of losing her and his thoughts about her extended longevity should she complete her Aramente. Nevertheless, he wanted to ensure that it would happen.

After killing Vorugal, Vax objected to Keyleth's desire to go after the Diseased Deceiver right away without the others, convincing her that they needed the rest of the party to do it and assured her that they wouldn't have to wait long.

In the middle of their battle with Ghurrix in the City of Brass, seeing Keyleth wounded, scared, and alone in the middle of the street, Vax flew down and kissed her, casting Heroism at the same time, to give her the courage and bravery she needed to see the battle through. When the battle finished, he hoisted Scanlan onto his shoulders and celebrated the heroism of both the bard and Keyleth. Despite her hesitancy and refusal of thinking herself to be a hero, Vax insisted that she deserved the praise.

On the night before Vox Machina set out to return to Emon to face Thordak, Keyleth took Vax and Allura Vysoren to her hometown of Zephra to enlist the aid of her people. It was then that she was reunited with Korren, who told her that he and his fellow druids would be joining the battle as well because he did not to stand by and do nothing while his only daughter was out there fighting. Vax mentioned that Korren was a good man, to which Korren asked that Vax prove to him that he is as well. And as Korren departed, Vax pulled Keyleth aside and told her before they returned to Whitestone, "I can't wait to come back."

In the aftermath of the battle with Thordak, when Raishan planned to fulfill her end of the deal and extract her information from the Cinder King's corpse, Keyleth told Vax to wait for her before doing anything. When Raishan began casting Speak With Dead due to a scroll, in his desperation to stop the dragon from fulfilling her goals, Vax attacked the Diseased Deceiver. Alas, his efforts were futile as the spell was successfully cast and, after being told that she would not leave Thordak's lair alive, Raishan flew further in, forcing Vax, Keyleth, and Vex to pursue and nearly get wiped out by the dragon's Meteor Swarm spell. In more than one instance, Vax's life was in peril during the brutal battle with Raishan and Keyleth did what she could to keep her lover alive, even though she nearly died herself when attempting to cross a river of lava. Despite the party's best efforts, the dragon ultimately escaped with Thordak's corpse in tow, the pair's vow to slay her now unfulfilled.

In the aftermath of the battle with Raishan, Keyleth expressed that both she and Vax deserved to bear part of the blame, but Vax told her that they did what they had to do in order to attempt to stop the dragon from fulfilling her goals. Later, before going to bed in Castle Whitestone, Vax tended to the remnants of Keyleth's charred and shortened hair, gently cutting away the burnt ends. He then told his lover that her new hairstyle looked good on her. He also comforted her and told her that he had seen her growing strength, that she was doing the best she could with what she was given and that she had never backed down. He also told her that despite her growing doubts, she needed to mix them with Vax's faith in her as well as everyone else's faith in her. Keyleth then confessed that Vax and the rest of Vox Machina were her first and longest-lasting friends and that they were family to her. They then both promised to go with other to wherever they wished once everything was behind them: Keyleth with Vax to "the theatre" and Vax with Keyleth to Zephra.

Vex'ahlia's Reactions to Keyleth and Vax'ildan's Relationship
Vax didn't talk to Vex'ahlia (his twin sister) about his love for Keyleth, which caused some tension between them. For the most part, Vex also seemed to resent their potential relationship initially and made a point of disturbing their private moments. When they returned to Vasselheim, she teasingly reminded them that Kashaw had kissed Keyleth. When Kashaw returned to Keyleth's life, however, Vex wasn't as resentful as expected and instead tried to encourage the druid to make her move with Vax, which she did when she openly kissed him after Grog's test of character against Earthbreaker Groon.

Vex continued adjusting to the reality of her brother's feelings, and after the party survived the slaughter of Umbrasyl, she asked Vax what was going on with him and Keyleth, but Vax refused to answer. Vex then asked how Keyleth feels about him, and Vax replied, "Ask her." So, Vex promptly asked Keyleth, who reluctantly admitted to having feelings for Vax and asked if Vex would hate her for that. Vex, after her death and resurrection, however, was no longer resentful and encouraged the druid to just be happy and not live in fear. Since then, she continued teasing her brother and Keyleth about their relationship, but she also stopped showing any further resentment, admitting to Keyleth that she cares.