O5-4

Short overview
05-4 is one of the thirteen overseers of the O5 Council, the most high ranking group in the entire SCP Foundation and ultimately have control over the Foundation's core operations.

In-universe description
The current O5-4 (presumed to be the one within the game given the timeframe of being moern day) is described to be an Australian (Koori) male of Canadian origin in his mid-40s, being a former Foundation field agent.

He has the title of "The Ambassador" for commonly working with the Administrator (a presumed highest position of power over even the O5 Council and also presumed to be the founder of the Foundation) in a more traditional ambassador role, as well as representing the Foundation in private meeting with heads of state and high-tier organizations such as the Global Occult Coalition or the United Nations. He has a sizable staff of diplomats under his command, and is commonly seen interacting with agents or representatives of external anomalous GOIs.

His anomalous ability is allegedly being able to travel vast distances in impossibly short durations on foot.

Five other Overseers have previously held the position of O5-4 - two deceased, one removed and contained, one defected to the Chaos Insurgency and one unknown - presumably still alive and associated to/working at the Foundation.

Appearance in game
O5-4 first appeared in the very first operation of the game, Operation Red Skies, where members of Mobile Task Force unit Epsilon-11 "Nine Tailed Fox" discovered that O5-4 was captured by the Chaos Insurgency. He was found missing when Epsilon-11 reached his office halfway through the recapture of Site-19 from Chaos Insurgency and rogue D-Class, where a message (written primarily in what is assumed to be blood) saying "Come Get Him" was smeared on the back wall of his office, with the Chaos Insurgency logo next to it. O5-4 was known to be the overseer missing as his keycard was visible on his desk.

The first - and likely only - time O5-4's character itself has made an appearance was in Operation Black Nightmare, where Mobile Task Force Alpha-1 "Red Right Hand" was tasked with rescuing O5-4 from within a Chaos Insurgency facility in Antarctica(? need confirmation). His character physically appears when you rescue him from his cell, and he will accompany you (or rather follow you) until you kill all insurgents and disable the four anti-aircraft guns on the facility surface. He is then extracted along with the MTF squad, and (presumably) returned safely to the Foundation.