I sometimes get so sad when I remember how Kiryu lost literally everyone that he'd ever loved in the span of a few days. Shinji, Reina, Yumi, Kazama, Nishiki—all of them died right before his eyes and he couldn't do a damn thing to stop it. He was so depressed by the end of Kiwami, ready to throw away his life, not caring if he ended up behind the bars for life.
Who did he even have left that he could go on for?
Date gives him a reason. The girl who looked a little too much like Yumi. And that sparks something inside him, something so unfamiliar it almost wreaks him from inside out. He couldn't save her mother, but he will die trying to protect Haruka. Because she's the only one he was living for anyway, right?
Who else did he even have?
Except, he had Majima too. He had always had him. Right from their first meeting in the hazy, glittering streets of Kamurocho in '88 to the violently ritualistic run-ins with him in the winter of '05, Majima was the only person who was a constant, grounding presence in his life, no matter how fluttering. This man waited 10 years for Kiryu to get out of prison, was tempted to follow him right in because fuck it, at least they'd be in that shithole together.
Majima is the only person still alive that Kiryu knows from before. And that's a big fucking deal. Majima knew Kiryu Kazuma before he was the "Dragon of Dojima". He knew him as the punk kid with ideals too lofty for their lawless world. In a way, they came of age together, and grew increasingly disillusioned with the Yakuza lifestyle, also together.
Today, Kiryu has more people he loves and more reasons to live than he did back in '05, but no matter how close they get to him, no one will ever get to see that part of him that long since got permanently buried in the rubble of the millennium tower.
No one but Majima, who knows and understands. God, he understands Kiryu so much. That's why, whenever they meet, they don't need to talk all that much. One glance, one fight and a couple of drinks later, it's like no time has passed and they're right back on that fated, glittery night at Tenkaichi, clashing for the first time ever.
Kiryu has spent his entire life protecting those he cares about. But Majima is different. Kiryu knows he doesn't need his protection. He knows that Majima wouldn't be killed simply because he had the misfortune of being associated with him. And so Kiryu subconsciously depends on Majima the way everyone else in his life depends on him. It's not entirely fair, maybe also a bit selfish but Majima indulges him, every single time, without asking anything in return.
So yeah, Date was right when he said that Kiryu had something precious to live for. Haruka, yes but also this crazy bastard of a man who would refuse to leave him alone for the better part of 3 decades.
And Kiryu loves him, goddamnit. There's just no simpler way to say it.