The amazing lexisblake translated this into Russian! Link is in my profile if you're interested.

恐れ Fear

Kasuka lives his life in fear.

Of course, with a brother like Heiwajima Shizuo, who plucks street signs like flowers and kicks cars like soccer balls, no one would be surprised to learn that that's the reason. But they'd be wrong.

"Aren't you afraid of me?" Shizuo asks him, just once.

He replies "Not really," and he means it.

He's not afraid of Shizuo. He's afraid for him.

The first time his brother displays his inordinate strength, hefting the family refrigerator over his tiny shoulders and then breaking under its weight, Kasuka is sure he's dying. He runs from the room, screaming for an ambulance for his groaning brother.

The sound of cracking, crunching bones haunts his dreams for days after every hospital visit for the next five years.

Eventually, Shizuo's bones stop breaking and his muscles stop tearing and Kasuka can stop being afraid that his brother will accidentally kill himself. Instead, he's afraid that someone else will do it for him. Shizuo has made many enemies with his strength, and one day one of them will get lucky with a crow bar to his head or a bullet to his heart, if Orihara Izaya doesn't end him first.

Even then, that's not what he's most afraid of.

Kasuka has spent almost as much time in the hospital growing up as Shizuo himself has, surrounded by doctors (of the legitimate and aspiring varieties) as he sits by his brother's bedside. Nobody is entirely certain of the cause, but Kasuka has his theories as to why Shizuo is the way he is. Shinra says his adrenaline limiter is broken. Kasuka thinks his rage limiter is also broken.

Shizuo's strength only manifests itself in moments of anger. He's not a clumsy Hulk, crunching doorknobs and denting elevator buttons whenever he tries to go anywhere. When he's not angry, Shizuo is just like any other normal person. It's his uncontrollable rage that signals his body to bend steel and crush cement. Shizuo hates himself for not being able to restrain himself and keep calm, but Kasuka doesn't blame him. If the limiter to restrict his adrenaline power is broken, then the limiter to restrain the rage that triggers the adrenaline might also be broken. It's not a flaw in his brother's character, but a flaw in his brain, and that is what frightens him.

After all, who's to say that Kasuka doesn't have the same flaw?

He's grown up seeing his brother in constant pain, spending his childhood in the hospital, being called a monster and regarded with fear and hate, lonely but terrified to get too close to anyone for fear of hurting them.

"Aren't you afraid of me?" Shizuo asks him, only once.

"Not really," he replies. He's afraid of having to live as Shizuo does.

So he clamps down on his emotions, terrified that one day if he loses his temper, he'll find himself with his back broken under the weight of lifting a refrigerator, or his muscles torn from the force of swinging a flag pole, or his knee shattered from kicking a car away. He buries his emotions deep down where he feels only a fraction of what a normal person does, and none of it shows on his face.

He doesn't know if he has the same flaws as Shizuo, and he's not about to find out.