Bellatrix stood in eager awaiting for Potter to arrive. The Dark Lord's plan was foolproof, even moreso now that she had assisted. She glowed with pride as she continuously replayed in her head how he'd informed her that she alone was suitable for the task. She jerked to attention as a twig snapped nearby. There was the Potter boy, in the flesh. She fought back the urge to kill him right then. It had to be the Dark Lord to do the deed. Yet the temptation remained, as did that tingling sensation she got when near the Dark Lord.
Voldemort stepped to Harry. "Harry Potter, the boy who lived, come to die. AVADA KEDAVRA!"
Bellatrix felt a rush of adrenaline as the Potter boy flew backward and landed on the ground, dead. Her heart sank, however, when she realized the Dark Lord was also laying motionless on the ground. She ran to him and began attempting to revive him. It took quite some time, but eventually, she felt life breathe into her, as though through him. It was an entirely exhilarating feeling, as though she'd won her first duel. Then, the Dark Lord opened his eyes. She smiled and nodded to him, telling him she had felt new life. She remembered him telling her in detail what would happen. When Harry dies, the part of my soul within him will most likely be destroyed. If that happens, the plan will have failed. However, if it survives, that part of me will not be able to remain with him and will seek out another entity. This must be within you. You will feel sheer power enter you, then you will know the invincibility you posses. Bellatrix smiled, knowing he had spoken truly. She stood and allowed him to do the same. Now, the task had truly been completed. Only the final victory now remained.