From Halopedia, the Halo wiki
Michael and Anarosa lost their father in 2549 and their mother in 2553. Michael lived with his sister in a simple white house at 7735 Killingham Street. One day in 2556 he got a call from the Oros Trading Company Headquarters on Mars while he was in the middle of eating, informing him of his sister's death in an accident. He stayed on the phone for nine minutes before disconnecting. Three minutes later, an Office of Naval Intelligence agent named Prauss arrived at his door, accompanied by a smart AI named Leo. When Michael first answered the door, he seemed bewildered and Prauss determined asking to come inside would have been a bad idea. They offered their condolences for his loss and explained that they were interested in procuring Anarosa's brain in order to create a new artificial intelligence like Leo. After patiently listening to everything Prauss had to say, Michael told him to go to Hell and shut the door in his face.
The pair returned to their vehicle and were nearly ready to give up when suddenly Michael exited the house and started walking toward them. Prauss started to apologize, but Michael cut him off and said he didn't want to listen to anything Prauss had to say. On the other hand, he did want to speak to Leo. Inside, the two were silent for a short while before Michael asked if Prauss was listening in. Leo admitted that he was. Michael mentioned that Anarosa had been offered the chance to be a donor before, but had turned it down because she didn't want to be involved in the military. Leo responded to this by telling him the AI created from her brain, were he to consent, would not be a military AI. Instead, it would be attached to an exploratory mission. Michael asked what being an AI was like. Leo had trouble explaining his existence in terms Carmelo could fully grasp and made sure that he understood that an AI created from his sister's brain would not be her. Anarosa was dead and nothing could change that. Michael broke down at this, but Leo comforted him by saying that he thought if Anarosa could choose to make her death have a positive impact on the world, that she would. Ultimately, Michael agreed to give permission for his sister to become a donor for AI creation.
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