(Covers information from Anderson's universe)
The Umbrella High Command is the leadership of the Umbrella Corporation.
Eighteen months before The Hive outbreak, Doctor Alexander Isaacs, co-owner of the Umbrella Corporation holds a meeting of the Umbrella High Command where he shows proof of the decadent state of the world and proposes "an orchestrated apocalypse" similar to the Biblical Flood that will wipe out the rest of humanity except for the chosen few preserved by Umbrella to repopulate the world afterwards. The Umbrella High Command ultimately agrees to the proposal and the T-virus is deliberately set loose upon the world, leading to the Global T-Virus pandemic.
Unwilling to go through with the plan but unable to stop Isaacs, Umbrella co-owner Alicia Marcus uploads a copy of a recording of this meeting to the Red Queen AI, knowing it will cause a conflict in her programing as the Red Queen is programed both to follow Umbrella's orders and also to preserve human life. As a result, the Red Queen takes drastic action during the Hive outbreak to attempt to contain the T-virus, an attempt that ultimately fails.
Following the beginning of the pandemic, the Umbrella High Command enters cryogenic stasis within the Hive along with thousands of other Umbrella employees to wait out the "apocalypse." Their role as the leaders of Umbrella are apparently taken over by Chairman Albert Wesker and the Umbrella Committee.
Ten years after the pandemic begins, former Umbrella security operative Alice, in reality a clone of Alicia Marcus, returns to the Hive guided by the Red Queen to locate and unleash a potent anti-virus that will kill anything infected by the T-virus upon contact and end the pandemic. While making her way through the Hive, Alice locates the cryotubes containing the Umbrella High Command and everyone else kept safe within the Hive.
Recognizing the importance of her discovery, Alice plants explosives from the Sanitation team's old equipment upon the cryotubes in order to destroy the Hive and kill all those within. After a dying Wesker drops the primed detonator, Alice's explosives detonate, destroying the Hive and killing all those within, including the entire Umbrella High Command. With the destruction of the Hive and the deaths of Isaacs, Alicia, Wesker and the Umbrella High Command, Umbrella is left leaderless and effectively destroyed.