Klaus continued to beat on the invisible wall long after the front door of the Gilbert home had closed. He was alone in an empty house, only a stone's throw from smoking ashes that only hours before had been his mischievious little brother.
Klaus threw himself at the witch's barrier, screaming "I WILL FIND YOU ALL!"
He sunk to the floor. His throat was raw, his voice going hoarse from screaming and cursing at the long-gone Gilberts. He drew his knees up to his chest and looked towards the kitchen.
"Kol," he whispered. "I'm sorry."
Tears welled up in his eyes and sobs threatened to take over his body.
"No." he growled fiercely. He would not cry.
Rebekah was the weak one, the one who cried. But not him. He was the hybrid: unstoppable, invincible.
A dry, humorless laugh escaped his throat. What had he told Caroline weeks before? Something about being the "Most powerful creature on the planet". The most powerful creature who had stood on the Gilbert porch, uninvited-locked out-watching helplessly through the open door as Kol burst into flames. He had tried to push through the invisible barrier, tried to answer his brother's painful screams. But the mighty hybrid could only stand outside and watch as Kol sank to his knees, and then fell to the ground.
"You should have listened to me, Kol!" Klaus snarled. "You should have trusted me."
The thought of his brother's trust delivered another shattering blow to his heart: Kol thought Elena and Jeremy were working with Klaus to kill him. Kol died believing Klaus had aligned with the Gilberts in driving the stake through his heart. He would never know that Klaus stood outside, hearing every word, but helpless to save him.
Just like he couldn't save Henrik.
The thought of Henrik's lifeless body in his arms sent a searing pain through his chest. The pain was literally suffocating. Klaus hated feeling so helpless.
Klaus flew to his feet and sped into the barrier again, bellowing in pain and rage. He sped into the wall on the other side of the room, slamming his fists into it, howling with pure hatred "I WILL KILL YOU ALL! I WILL KILL EVERYONE YOU LOVE!"
Just like they had killed someone he loved.
Kol was often mischievous and always obnoxious, but despite everything over the centuries, Kol was his little brother.
And now Kol was gone forever.
Klaus felt a hole in his heart, as if he himself had been stabbed by the White Oak Stake. The hole where his love for his brother had been tucked away. As he looked toward where Kol's body lay, his love was replaced by a bitter mixture of heartache, hatred, and regret, and not for the first time in all his many years, Klaus considered taking his own life.
The wolf inside him howled with rage at the very thought of suicide.
As he slammed himself into the wall a second, third, fourth, and fifth time, he felt his humanity begin to slip away.
He dropped to the floor, his eyes turning the hateful yellow color that belonged to the wolf, and he felt his bones begin to break. As he turned, he welcomed the physical pain that pushed away the emotions.
When the transformation was complete, Klaus stood in the center of the living room in the form of the jet black wolf. He spun around wildly and crashed into the witch's barrier again.
With an angry snarl, he turned and pounced on the couch, tearing into the fabric with his teeth, and ripping it with his claws. He shredded the couch in minutes, then turned to the coffee table. He dove on it, and it instantly shattered under the weight of the wolf. Klaus snapped and splintered it, piece by piece, then turned to the end table covered in family photographs. One leap sent the frames to the floor, shattering the glass, as Klaus desperately sought to make someone, anyone, or anything hurt the way he hurt.
This continued for about an hour. The lamps, the carpet, the chairs, and curtains, until the entire Gilbert living room was in shreds and splinters.
When it was over, the great black wolf sat down, facing Kol's body. He lifted his head and let out a sad howl that pierced the empty house.
As Klaus continued to howl, his body turned back to his natural form, the wolf's howl replaced by Klaus' anguished sobs.
"Kol. Kol" he choked through his tears. "I'm sorry I didn't protect you".
Klaus leaned his body against the barrier, getting himself as close to his brother's body as he could.
"I'm sorry for everything."
Klaus had always prided himself on his ability to track his siblings down wherever they went. But his little brother had gone to the one place he couldn't follow.