If you hadn’t read the forerunner saga books please don’t read the rest of the post.
Spark was not completely destroyed, however. Between 2553 and 2557, the UNSC detected a transmission from the ruins of Installation 00 and deployed the UNSC Rubicon from Luna to conduct a further investigation. A Remote Contact Team recovered an extremely damaged armature, believed by the team to be the source of the signal picked up by the initial investigative group. The device was actually the broken, barely active remains of 343 Guilty Spark.
After properly calibrating their AI translator, the human team began to interrogate Spark, hoping to gain insight into the ancient human-Forerunner relations and the Didact. Spark, acknowledging the humans as “the true Reclaimers” and claiming that his duty was to eventually testify to Reclaimers when given the opportunity, proceeded to describe the events that led to his former human self becoming a monitor. Over the course of his narrative, he constantly accessed the ship’s information stores, breaching the firewalls without effort, much to the ONI team’s dismay. As a result of the extensive damage he had sustained, Spark’s memory was heavily splintered and barely functional; for example, he was unable to remember many of the preceding events, only learning of his recent interactions with the humans after tapping into their records and even then, assuming the monitor in question being a separate duplicate of himself.
After Spark had finished his story, his robotic shell finally powered down and was jettisoned into space by order of the ONI team commander. Before this, however, he had successfully managed to upload his data stream into the ship’s computers, disabled its AI, and took full control of the vessel. Having come to the conclusion that the Librarian was alive as a result of long study, and that he had need for the ship and its crew, Spark put them to sleep and set course to where he believed the Librarian could be found.
Which I think Spark will make a return in Halo 5. If not in the campaign but maybe spartan ops. Do anybody us want him to show up in the new halo 5?
Thank you Halo Wiki