Send "I'd die for you." for my character's reaction.
Kasuka has always been slightly bitter, for the way he turned out – casing up his emotions and unable to express anything unless he was acting. For a while, he blames it on Shizuo, and how he had to be the opposite to his brother’s blinding, explosive temper. For a while, he hates his brother just a little bit, though of course it doesn’t show and he doesn’t express anything like it and instead carries on with how things had been before. For a while, he’s bullied, for his ‘freak’ for a brother and how it made him a freak himself.
Eventually he grows out of the hatred, once he sees how much Shizuo hates his temper and does want to change but doesn’t know how to go about doing it. Instead of hating him, Kasuka sympathises, if only slightly. It upsets him to see his brother treating himself so harshly and getting into all those fights with Orihara-san and injuring himself all the time, even if he had built up a resistance and heals quickly.
Somewhere along the line the hatred is completely gone (the bitterness is there, just lesser, and aimed more towards himself) and he doesn’t see Shizuo as anything other than the brother he loves. They move on with life and he becomes an actor and his brother changes jobs all the time, and Kasuka knows that his nii-san would do anything to help him – has beaten up countless people and stopped those who wished to harm the actor with a flick of his wrist and a flying sign.
It had come to be that they love each other dearly (always had, they’re brothers, it’s impossible not to even if the feeling is drowned out for a little while) and as far as Kasuka knows, they really would do anything for one another. At least, he certainly would for Shizuo.
It had never been hard to guess that the ex-bartender felt that way; that he would sacrifice himself, the human who views himself as a monster, for the monster who only wishes he could be human.
Hearing it coming from the blond’s mouth is a whole other matter.
There’s a moment of silence before the younger steps forward and wraps his arms around his brother’s waist, pressing his forehead against Shizuo’s shoulder and squeezing him tightly.
All he says is, “I know.”
And he doesn’t mention the fact that he would do the exact same thing.
He looked up in thought. Shizuo was happy his brother also was looking foward to it. Now he just had to think about the options, Shizuo thought for a moment, but all that came to his mind were Russia Sushi and some cafes. “Well, we could go to a cafe.” He wouldn’t take Kasuka to Russia Sushi for nothing. He was still convinced they used people in their dishes and he didn’t want to expose his younger brother to that kind of place.

Kasuka nodded in agreement, pretty much happy to go anywhere, so long as it met the two requirements. (A: Shizuo had to be there, if only for today and b: there had to be pudding of some kind.) “Okay,” he said, and started walking in a random direction without much thought, not really caring if it was the wrong way or not. “… Which café?” Perhaps knowing the name of the place would actually help him in finding the way, rather than ending up at Russia Sushi and eating people.
”Aniki,” Kasuka greeted in return, still plain featured but somehow looking happier than he had been before. ”I’m fine. Work is still a lot of fun,” he said, and then asked, ”Have you been well?”
“I see.” He said taking his hand away from the other’s head. “What about we go somewhere and grab something to eat? I was heading to have dinner anyway." He knew how Kasuka loved to work and he felt happy when the other was out so at least he would be safe from all the mess that went around in that city, but still, seeing him back was nice and Shizuo thought that going out to eat something sweet with his brother wouldn’t kill, right?
Spending time with Shizuo was such a rarity these days that it barely took two seconds for Kasuka to agree. ”I’d love to,“ he voiced, knowing that even if he was going to be on break for a while, there would always be times where he would be unable to talk to his older brother. Making the most of it, whilst they still could, was a good plan. ”Where do you want to go to eat?“ As long as there was pudding, Kasuka didn’t really mind.
”Aniki,” Kasuka greeted in return, still plain featured but somehow looking happier than he had been before. ”I’m fine. Work is still a lot of fun,” he said, and then asked, ”Have you been well?”
“Just fine. The usual, y’know.” He said placing one hand over the actor’s head and ruffling his hair gently. “How long are you staying around this time? Maybe we could catch up for a dinner or something.”
Kasuka’s head ducked along with the ruffling, though he didn’t seem to mind the action, since he didn’t make to move away. “I’ve been put on a break,” he answered, almost seeming displeased at that fact. “I’m going to be free for a while.”

”Aniki,” Kasuka greeted in return, still plain featured but somehow looking happier than he had been before. ”I’m fine. Work is still a lot of fun,” he said, and then asked, ”Have you been well?”