Okusei was sitting up and it was literally the only thing anyone wanted to talk about.

Mining yield? Sure, but how was Okusei's balance?

Updated blueprints? Yeah, yeah, but how long could he sit up on his own?

And Kohaku had been busy with mining, so Senku was covering her baby-watching shifts even though someone else probably could have, because a silly little part of him wanted Okusei to still have that time spent with one of his actual parents and not the squad of aunts and uncles ready to swoop in at a moment's notice (he appreciated them—but he also wanted to be part of his kid's life).

So he got the questions. Constantly. From people whose names he didn't even know, even though he was able to remember everyone he supervised, which meant these were just everyday people.

And the kid was getting heavy. But Senku didn't dare set him down, because he'd be swept into a crowd of admirers and Senku would have a hell of a time getting him back. (They wouldn't hurt the kid, he knew that. But it would slow down work massively.)

So, begrudgingly, Senku had asked Tsukasa if he knew anything about lifting weights—he had to get stronger if he wanted to easily carry the little chunk his son was developing into (and he did).

Tsukasa had, professionally, not raised an eyebrow at the request, simply nodding and asking what his goals were, that he could help develop an exercise plan.

Part of Senku wanted to die of embarrassment. He knew he was scrawny. It was just something he'd come to accept—he didn't have the genetics for a big build, and his preferred occupation didn't require lots of manual labor. Any working out he did would probably be pathetic and laughable, at least at first.

But his desire to be able to easily carry his son around was a massive motivator, and he didn't have time to waste being embarrassed about something he couldn't change about himself.

Even better, once informed, Tsukasa had actually gotten pretty excited about it, and was able to develop a plan that had Senku basically helping out with mining, carrying, squatting, lifting, and so on, so he wasn't doing 'useless' workouts like just lifting weights. Senku had never seen Tsukasa excited before and it was a bit weird.

Even Kohaku noticed. "What's got Tsukasa all fired up?" she asked with a grin at lunch that day. "Are we starting a boxing competition?!"

Senku chuckled. "Not even. He's, ah, helping me with something."

She raised her eyebrows expectantly, adjusting Okusei as he ate.

Senku tapped his fingers on his leg. "It's, ah…well, the kid's gaining weight."

"As he should."

"Absolutely. He's developing at just the right rate. Happy, healthy baby, ten billion percent." Then he sighed. "But I'm not…especially strong. And…I want to still be able to hold him as he gets older." He cleared his throat and sat back a little. "So I'll probably be helping out at the mines some days."

Kohaku looked at him, then at Tsukasa. "Is Tsukasa making a road map for you, then?"

The comparison to his scientific roadmaps startled him and he laughed. "I guess so. The road map for 'Senku's Strength Building.'" Working out was science, too.

Okusei grunted, done eating, and Senku took the kid so Kohaku could put her clothes back in order. Okusei sat on his lap, blinking his big eyes drowsily, grabbing at Senku's thumb as he held the kid upright (the kid could sit, but it was early days yet—no need to risk a sleepy baby fallover).

Senku snorted. "I don't think I was ever this cute as a baby. My dad said I was a brat right from the start and he had video evidence to prove it. I bet the kid gets it from you."

Kohaku hummed. "Yeah, Luna and Chelsea were saying modern people took lots of pictures and, uh, 'videos' of their babies to have as memories for later. Did your dad have lots of pictures of you?"

He didn't answer right away and felt Kohaku's eyes land on him as he continued in silence. "Ah…no. I…never actually saw my baby pictures."

"…because of your parent?" she asked softly.

Senku nodded and rubbed Okusei's back. Byakuya had done the picture taking—he always had—so it was likely that any photos were of Senku and his parent, and thus unofficially 'off-limits.' And now lost forever.

She sighed. "Your dad must've loved your parent a lot."

"Best friends. That's all he told me."

"Do you think he liked them romantically?"

He shrugged. "It's crossed my mind, but it's pointless speculation."

"A waste of time?"

"Yeah." They sat quietly for a bit longer. Senku sighed and eventually added, "I'm more inclined to think they were like siblings, though. My dad didn't really do romance. And…he either didn't have living family or didn't interact with them at all."

The older he got, the more he realized how…awful his dad's life had been. What he'd given up or gone without. Who he'd lost, who'd left him behind. And the Hundred Tales—in the message for Senku, there had been hints of an even sadder ending to Byakuya's story, of one man left alone against the world.

And yet he had been the happiest, most loving man Senku knew. His adversities had not hardened him into unfeeling stone or cruelty—he had been genuine and optimistic, fun and charismatic. He'd left a legacy of knowledge and adventure. He'd never, never given up.

"Ba," Okusei said, which startled Senku right out of his reverie.

"What?"

"Ba."

"Was that a word?!" Kohaku cooed, crowding close.

"Not even. Just mouth noises."

"Ba."

"Ohh, but it's so cute! Good job, Okusei!" Kohaku said, tickling under Okusei's chubby little chin. "Ba!"

"Ba!" returned the kid with a sleepy flail.

"Who's my smart little boy?" she cooed, snuggling against Senku's side. "Such a clever boy."

"Thanks," Senku said with a grin and Kohaku lightly whacked his arm.

"Not you. You're a pain."

"Aw, not smart enough for you?"

"More like a smartass."

Senku laughed. "How cruel, lioness. You'll break your husband's heart, talking that way."

She leveled a glare at him. "You'll get over it."

Just as he was considering whether or not he wanted to kiss her, he heard giggling from behind them and sighed. When he turned his head, sure enough, there was his 'fan club,' and it seemed Luna and Suika had joined them for lunch today. All of them were watching him and Kohaku and giggling, cooing, and swooning, and Senku felt his eye twitch.

"Alright, back to work," Kohaku said, standing up and taking Okusei from his arms. "Francois has him for nap time, right? I'll drop him off and see you at dinner!" And was gone.

And Senku definitely did not pout as he got back to work. He was looking forward to his first day at the mines, though—he wouldn't bulk up just sitting around! So he threw himself back into blueprints and testing, determined not to fall behind even as his plans and goals continued to change.