A/N: Warning for character death and angst, everyone's a little OOC, especially Zim. No flames, please!
Dib hissed a cry of pain and stumbled to his feet, narrowing his eyes at Zim. "Back off, filth." Zim snarled.
"Never!" Dib growled stubbornly. "I'm not going to let you take over my planet."
Zim's black-gloved fist connected with Dib's jaw, sending the human to his knees with a moan of pain. Zim pulled a glove off and unsheathed his claws. "Then you're going to die here, alone. And no one will care."
Dib blinked up at his enemy, his vision blurring and his mind slipping in and out of focus. "I w-won't give up…that's not true…" He wheezed, every inhalation edged with pain as he breathed.
Zim laughed, cruelly driving one of his boots into Dib's stomach, making him gasp and buckle in over his mid-section. "Isn't it, human? No one cares for you here. They don't believe you, and they'll regret it. Oh, they'll regret it." Zim's blood-red orbs shone brilliantly down at Dib, a triumphant smirk plastered across his face.
Dib's eyes watered and he wheezed out a reply of, "No! You won't do this…I won't let you…"
"Really? I'd like to see you try to stop me." Zim said with an amused chuckle.
Dib moaned, collapsing into a fetal position as Zim darted forward and raked his claws across his face. Blood pooled and streamed down his face in thick rivulets. His scythe hair fell out of its place and hovered in front of his eyes, further crippling his vision.
"N-no…" He gasped.
Zim sighed in exasperation. "Succumb to the mighty Zim and it doesn't have to be like this." He said patiently, crouching down beside the boy and cupping the side of his face with his still unsheathed claws.
"Never!" Dib shouted with the last of his strength.
The once proud paranormal investigator groaned and dropped his head in defeat. His breathing had grown ragged, his heart racing at a fractious pace. Zim twisted his lips into a sneer and kicked Dib onto his back.
Dib groaned and tried to back away, but Zim drove his boot down onto his chest, holding him in place. The alien sneered down at his fallen enemy and his eyes took on a malicious glint. "After all these years, Dib. I would've thought that you'd know better than this." Zim shook his head in disgust. "I suppose I'll have to kill you then."
Dib let out a strangled sob. His family-if you could call it a family- wouldn't even notice his absence. He met Zim's vindictive glance, honey eyes glazing over with pain.
"Any last words, human?" Zim demanded as he extended his spider legs from his PAK.
"I-I'm…" He wheezed, ignoring the tears falling from his eyes.
"What? Spit it out!" Zim snarled impatiently.
"I'm sorry…" Dib forced out.
Zim looked taken aback. "For what?" He asked, momentarily forgetting his lust to kill the human.
"Trying to stop you…I wish I could…change it…" He managed to say.
Zim's eyes widened. "I'm sorry too, Dib." Then he drove the sharp metal tip of the leg through Dib's throat, ending the boy's life quickly.
The spider legs retracted and Zim fell to his knees, cradling Dib's head in his lap as the boy took his last breath of air before dying in Zim's arms. Zim cried for him. For everything he'd done to the boy in the past. He wanted it back.
After mildly regaining his composure, he used his PAK to call Gir over the communication line. "Gir?" He asked softly.
"Yes, my master?" Gir shouted, glowing crimson.
"Shut down the base." Zim ordered flatly.
Gir obediently dashed over to a set of controls and hit a set of buttons with the occasional switch of a lever. When the task was finished and Zim could hear the faint sound of the countdown, he gave his final order to Gir.
"Now self-destruct, Gir." The little robot glowed scarlet once more, before exploding.
Zim cut the transmission and lifted Dib's lifeless body into his arms. He carried the boy out of the alley and into the middle of the street. "Humans!" Zim screamed, throwing off his disguise. "Come witness!"
Several people came out their front doors and realized an alien was standing there, holding a dead boy in his arms. Gasps went up as they formed a loose ring around Zim and Dib.
"This boy is Dib Membrane, son of Professor Membrane. I killed him!" Zim proclaimed. "I am an Irken Invader, sent to infiltrate your planet and destroy it." More gasps of shock and horror went up through the crowd.
"But fear not! I have destroyed my base and my servant, so there is no need for panic." Zim took a deep breath, ignoring the tears threatening to spill out. "No one believed this boy in my existence, and when he died for you filthies, no one cared. I am all he had, and I betrayed him. I cannot bear to live with that."
Zim gently laid him on the street in front of him. "And so now, I will take my own life for him." The welled up tears came forth, spilling down his cheeks. "This is Invader Zim of the Irken Empire, saying goodbye."
He extracted the spider legs from his PAK and lifted one to his throat. "I'm sorry, Dib…" He whispered before plunging the steel tip deep into his own throat.
Zim hit the ground, and with his dying breath, he interlaced his fingers with Dib's, joining them together in death as well as life.