One common theme is the idea of redemption. Often, the OC tries to bring out a softer side of Esdeath, as if redeeming her from her cruel ways. Another theme is the power dynamic. Since Esdeath is a powerful character, the relationship with the OC often explores how power affects their interactions.
Esdeath's character can be developed by exploring her backstory in relation to the thief. Maybe she had a similar experience in her past where she was an outcast like the thief. This can make her more empathetic towards the thief. The thief's character can be developed by showing their growth from being a simple thief to someone who has a greater purpose, perhaps influenced by Esdeath's grand plans. As they interact, both characters can change and adapt, making their relationship more complex and interesting.
One plot idea could be that the thief is initially stealing from Esdeath's domain. Esdeath catches the thief but is intrigued by their skills and instead of punishing them, forces the thief to work for her. As they spend time together, an unlikely bond forms between the cold - hearted Esdeath and the wily thief.
Tatsumi is very likely to be involved as he has a significant relationship with Esdeath in the original story. Her subordinates in the Jaegers might also be part of the fanfic. They could be shown as being protective or having mixed feelings about her pregnancy.
One popular 'Esdeath x OC fanfiction' is 'A Frozen Heart's Thaw'. It delves into the relationship between Esdeath and an original character in a unique way. The OC in this story has a backstory that intertwines with Esdeath's cold nature, gradually melting her heart through a series of adventures and emotional exchanges. Another great one could be 'Esdeath and the Unlikely Ally'. Here, the OC is a character with a different ideology than Esdeath at first, but as the story progresses, they form an unexpected bond.
Truth Listener was a spiritual divine beast that lay under Ksitigarbha Bodhisattva's scripture table. It had a very powerful hearing ability. It could recognize everything in the world by listening, and it could even hear all the information about all the living beings in the three worlds. Truth Listener's strength was described as being comparable to the Jade Emperor's clairaudient. It was even believed that his Dharmic powers were higher than the Jade Emperor's. In Journey to the West, Diting was summoned by the Jade Emperor to help distinguish between the real and fake Monkey Kings. In Fantasy Westward Journey, Truth Listener was also a rare and special Summoned Beast. It had the talent skill of Observing All Creations and could release special skills and small and large skills in one round. Truth Listener's strength was considered very powerful. Some players had even synthesized Truth Listener with 12 skills. It carried four special skills and instantly killed everyone in the arena. In short, Truth Listener was considered a very powerful Divine Beast with its outstanding hearing ability and strength.
According to the story, a good listener should show empathy. That means trying to understand the feelings of the speaker. If someone is sad while talking, you can give a sympathetic look or a gentle touch on the arm to show you care. Also, don't interrupt. Let the person finish their thoughts before you start to talk. This gives them the respect they deserve and also helps you to fully understand what they are trying to say.
The story might suggest that respect is a big part of being a good listener. Respect in terms of not cutting in and allowing the speaker to have their say completely. Also, having an open mind is important. Don't judge what the person is saying right away, but listen with an open heart and mind.