The Human Expedition was a league of Alliance military and civilian groups that fled to Kalimdor during the Plague of Undeath. They were led by Lady Jaina Proudmoore, who was determined to find a safe haven for her people, she being the only human who listened to the Prophet Medivh and fled.
While called the "Human Expedition", the military forces had dwarves and high elves as well as humans, and it is possible members of the Alliance races were also amongst the other human civilians that traveled with them.
The Human Expedition was composed of several groups, including:
- The "Human Expediton" — Besides the complete organization, the term Human Expediton is used to refer a faction within the group.
- The Lordaeron Corps — Lordaeron's elite soldiers guarding the expedition.
- The Lordaeron Brigade — A brigade of humans from Lordaeron.
- The Gilneas Brigade — A brigade of humans from Gilneas during the plague.
- The Kul Tiras Elite Corps — A force of humans troops from Kul Tiras likely the Lady's personal Guard.
- The Stromgarde Brigade — A brigade of human troops from the Stromgarde.
Following the Battle of Mount Hyjal, the majority of the members of these parties settled on Theramore Isle in Dustwallow Marsh under the wise leadership of Jaina Proudmoore. These forces would soon become part of the Theramore army. It is likely that many of these soldiers would later form part if not all of the 7th Legion.
It is implied in Warcraft III that the Expedition was most, if not all, of the survivors of the Eastern Kingdoms. Garithos' and Kael'thas Sunstrider's forces were revealed later, but their existence does not contradict this, as they were simply forgotten stragglers. The arrival of the Kul Tiras navy doesn't contradict this either as they were out to sea during the plague and said to have gone back to the main land one last time to look for survivors.
This was not proven to be false until the release of the RPG books where it is told that many of Lordaeron's survivors of the plague fled for refuge to the south into the lands of Khaz Modan and Azeroth. ( Some of the earlier passages continued to hint at them being most of the survivors with humans on Theramore, dwarves and gnomes at Bael Modan, and Wildhammers on Hyjal. It could be that the people who fled to Kalimidor actually thought they were the only survivors as the RPG books state that for a long time it was hard to get news about the Eastern Kingdoms by ship across the Maelstrom safely. )
We can also suggest that the nation Theramore are even not half of the survivors of Lordaeron since during the Third war Stormwind soldiers had taken the Alterac Mountains and repelled the Scourge on Chillwind Camp. Also Garithos' forces managed to repel them on Silverpine Forest on the borders of Dalaran and therefore the people of Lordaeron were capable of escaping and even took refuge on Hillsbrad Foothills. It is also revealed that Jaina Proudmoore had taken half of the Kul Tiras fleet. It also suggested that most of the people of Theramore were sailors of Kul Tiras. This is also making sense since when Admiral Daelin Proudmoore arrived to Theramore, Jaina's forces immediately started to obey him. We can speculate that most of the people of Theramore are sailors of Kul Tiras, And refugees of Stratholme that had nothing to lose anyway since their homes and families were butchered by Arthas. This is also explaining why there were many Paladins and Silver Hand Knights with her.