A cinematic for "Halo 5: Guardians" has leaked online, according to a report at Gamespot.
The video briefly shows Agent Locke speaking with the Arbiter in regard to trust. The clip actually starts with Locke being told by another Sanghelli that he is not trustworthy, before the Arbiter comes into the scene to continue the conversation. The Arbiter then interrogates Locke on his job and his current mission objectives.
The video reportedly comes from a Twitch stream of "Halo: The Master Chief Collection." Someone who purportedly viewed the stream reported on Reddit that the streamer didn't mean to show the new cutscene...which explains why the video ends so suddenly.
Most noteworthy in the clip are the recognizable voices of Keith David, playing the Arbiter, and Mike Colter as Jameson Locke. From this one can gather that Agent Locke is front and center as the lead character for this new game as has been speculated for some time.
You can watch the brief snippet below, and form your own opinions. "Halo 5 Guardians" will be released on Xbox One early in 2015.