Halo: Uprising Issue 1
From Halopedia, the Halo wiki
The issue opens with John-117 on board the Forerunner Dreadnought, which is currently passing Jupiter. He is contacted by a UNSC facility on Io, but stays silent and moves on, killing a group of four Grunts, then a pair of Jackals, then another Grunt quartet.
As this happens, the scene cuts to an interrogation of Colonel James Ackerson, captured by the Covenant aboard the CCS-class Battlecruiser Triumphant Declaration. He is about to be killed in celebration of the defeat of Earth before he coaxingly states that if "The Covenant attack Earth...they will never find the key." The Brute Captain interrogating Ackerson is intrigued by this, and uses a large knife to lacerate Ackerson until he reveals more information. Ackerson states that this key, if not found, will force the Halos to malfunction "like they did before". He also said that it is hidden in the city of Cleveland, and that it is called the Key of Osanalan.
Before he can reveal more, he falls unconscious, leaving the Brutes confused and worried. A new, self-doubting character named Ruwan Ackerson is introduced who serves as a concierge for a high-line motel in Cleveland under attack by the Covenant. He meets Myras Tyla, a performer staying there who commandeers several weapons from a dead Marine and manages to escape with Ruwan. They try to flee in vehicles but find the road blocked, and are finally herded together with what seems to be most of the population of the area into a stadium, where the Covenant declare that to live they must find and give to them the Key of Osanalan. Myras is confused, but Ruwan states with certainty that he "knows exactly what that is."
The Master Chief, in the meantime, finds himself faced by an extremely large force of Covenant troops, including at least three Hunter pairs, who fire on him simultaneously. He is hit by several beams and falls to the floor. A Brute Chieftain begins to crush him with his foot, saying that the Master Chief will tell them "where the Key is...after they remove enough parts of his body".