(I started writing this a little before I actually got to play Death of the Outsider, so the setup of Billie's cabin is a little off, but it's otherwise canon-compliant. Summary text is from the "Goodbye Karnaca" journal found in Dishonored 2.)
The creak of a door hinge caught Billie's attention, and she looked up to see Daud standing just outside her private cabin, his hand on the rusting metal grip.
"I usually keep that locked up tight when I have anyone else on board," she said pointedly. She should have locked it this time, too, but it had been just her for so many months now.
"I can see why," Daud said as he stepped inside. A smile passed across his face as he caught sight of the faded wanted posters on the wall, and he reached out to smooth a folded corner on the one bearing her name. "Might scare away some of your paying passengers."
"Well, lately I just seem to be housing folk for free," Billie said drily.
Daud let his hand drop to brush across the edge of the old whaling mask on the desk below, then drift over to the audiograph player sitting beside it. His fingers hovered over the controls, and he looked up to shoot a questioning glance in Billie's direction.
She hesitated for a moment but eventually shrugged and nodded her permission.
He flicked the dial to turn it on, and Billie watched as his eyebrows shot up at the sound of his own voice playing through the horns. He let it go on for only a few seconds before quickly switching it off again. "Where did you find this?" he asked.
"Black market dealer," Billie said with another shrug. "They dug up a lot of old Whaler junk when they drained the Flooded District, and not all of it made it into the hands of the Royal Spymaster like it should have. I've picked up a few logs and journals over the years, too. Burned most of those, but this cost me too much for that."
Daud shook his head. "Not worth the card it's recorded on," he muttered
"Maybe, but I didn't do a great job of haggling on it. Guy could tell how much I wanted it, so he wasn't giving me any deals." She took a step forward and leaned against the doorjamb. "I missed hearing you," she admitted softly. "I probably would've paid even more if he'd pushed for it."
Daud looked up to meet her eye, held her gaze for a long, silent moment. Then he turned away, shoving his hands into his pockets with a snort. "I'm sure you could have found some other old man who'd smoked his throat raw to bark a few orders at you."
"No one barks an order quite like you," she said with a shake of her head, letting herself grin, "and if you expect me to believe you didn't come into this world growling at everyone like that from day one…"
He started to laugh, a rare but familiar old sound that made Billie's grin grow wider.
Then he started to cough.
He brought his fist up to his mouth as he doubled over, throwing his other hand out to brace himself against her desk.
Billie's smile vanished. She took a step forward, but Daud shook his head sharply, stopping her in her tracks. She watched anxiously, helplessly, as dark, shining drops of blood flecked across his glove.
The hacking subsided into heavy, labored breathing after a few moments, and Daud pulled his hand away from his face with a grimace. "Damn," he muttered, leaving a streak of red behind as he wiped his hand off on his clothes. "We've got to finish this soon."
Billie frowned deeply but followed him out of the room to the board where her map of Karnaca was pinned up. She made him sit and drink down a glass of water before she let him brief her on his plan, and she was distracted during much of it, her eyes drifting constantly back to that smear of blood.
I only just found him, she thought miserably, watching as he stood up on shaking legs and began to scrawl notes across her board in his neat, familiar hand. I'm not ready to lose him again so soon.
With Daud's back turned to her, Billie closed her eyes and let his words wash over her, soaking in the sound of his voice while she still could.