Dear Hongrang Episode 5 opens with a brutal flashback—Kkot-nim, pregnant at the time, is stabbed in the stomach by Yuk-son, Yeon-ui’s assistant. He coldly claims it was under Yeol-guk’s orders. Though she survives, she loses her child. Sometime later, she adopts a young boy—an orphan who had just escaped captivity—and raises him as Fake Hong-rang. In the present, she warns him not to get too close to Jae-yi. Her long-term plan is to eliminate the Sim siblings and place him at the head of the Min Guild. While Hong-rang insists that Jae-yi can be useful, Kkot-nim indulges his soft spot but instructs her assassins to kill the girl if she becomes a liability.

Mu-jin, on the other hand, is furious with his aide for issuing a kill order without consent. He regrets having put Jae-yi in danger. Coincidentally, Jae-yi brings up the rumor that Hong-rang is the infamous Soulless Reaper and asks Mu-jin if it’s true. He confirms that Hong-rang is indeed an assassin, which only increases her concern for him. She confesses that although she doesn’t accept him as her brother logically, her heart instinctively feels a bond with him. This confession saddens Mu-jin, who is secretly in love with her.

Meanwhile, Hong-rang pokes around Jae-yi’s secret hideout and discovers drawings of Little Hong-rang. One picture features a sachet he instantly recognizes. Jae-yi catches him snooping, and he quickly pretends he’s recovering lost memories. She asks him to tell her more about his assassin life so she can accept this new version of her brother, but he avoids the question. Later, he questions the palace cook about the sachet and learns that it’s a family protection charm. Little Hong-rang had lost his, and from then on, he always wore Jae-yi’s. A flashback shows Kkot-nim and Fake Hong-rang burying the original sachet that Yeol-guk had made for her unborn child.

The Min Guild faces a major setback as patrons pull their support. Yeon-ui takes drastic measures and kills the Jin verifier, staging it as a suicide. She includes a fake note claiming the Sims had no knowledge of the forged paintings. This sways the patrons, who return to the guild out of guilt. As repayment for clearing Yeol-guk’s name, Yeon-ui demands that Jae-yi be married off. Yeol-guk is furious—he doesn’t want her used like a chess piece—but he holds back, knowing how dangerous it is to cross Yeon-ui. He redirects his focus to Gyu-ha, suspecting he’s plotting something.

Hong-rang finally unearths the buried sachet and plans to use it to prove he’s the real Hong-rang. Since Jae-yi believes only one exists, she’ll have no choice but to accept him. But just as he’s about to hand it over, he sees her sharing a tender moment with Mu-jin. Overcome with jealousy, he confides in his dog Goldie that he’s not ready to give it up. If he does, she’ll only see him as her brother.

Later, Jae-yi visits a gambling den asking questions about the Soulless Reaper. No one dares answer. Suddenly, she’s kidnapped by Bang-suk, who claims he’s found the real Hong-rang and demands revenge in exchange for proof. But Jae-yi turns the tables, later telling Hong-rang that even if he’s an impostor, she doesn’t want him harmed—she cares for him now. As it turns out, Bang-suk had lied about the real Hong-rang. A fight breaks out between his thugs and Hong-rang.

Kkot-nim’s assassins appear to assist in the battle, but their real mission is to kill Jae-yi. In a desperate plea, Hong-rang begs her to accept him. Knowing her life is in danger, he hands her the Sim family sachet and admits to being the Soulless Reaper. That’s all it takes—Jae-yi finally accepts him as her brother. In-hoe, watching from the shadows, orders the assassins to stand down.

A heartwarming montage follows with Jae-yi doting on Hong-rang. Though Mu-jin remains cautious, he agrees to hand over control of the guild. Jae-yi even brings Hong-rang to her secret picnic spot. However, things get complicated as Hong-rang, aware of his romantic feelings for her, begins blurring boundaries. He wipes sugar from her lips and licks it off her fingers, leaving her flustered and unsure of how to react.

Kkot-nim is livid. Her vengeance requires Jae-yi’s death, and she instructs In-hoe to kill her regardless of Hong-rang’s feelings. In-hoe is hesitant, but he receives unexpected support from Gyu-ha. Jae-yi, meanwhile, is set to marry into a questionable family. Her suitor is Choi Ju-yeol, who tries to charm her with discussions on art and Du-ryeong. He eventually opens up about his past losses, and she softens a little. Mu-jin wants to stop the marriage, but Yeol-guk argues it’s beneficial. If the Chois breach the prenup, their land goes to the Sims.

Still suspicious, both Mu-jin and Hong-rang investigate Ju-yeol separately. Their findings are horrifying. All three of Ju-yeol’s previous wives have either died or vanished. Hong-rang tracks down the third wife, Lady Ko, whose face has been grotesquely mutilated.

As the wedding day arrives, Ju-yeol cruelly beats a servant and then smiles as if nothing happened. Despite everything, the episode ends with the ceremony commencing, leaving Jae-yi walking toward a man whose true nature is darker than anyone imagined.