The Anti-Alliance is a major alliance formed in BB5.
The Anti-Alliance was formed the day the game began, by the apparent leader Violet. She and NP had devised a plan to control nearly the entire house between the two of them, Violet choosing to make a group unexpected to most of the house due to having been enemies with both Celever and Mariano in past seasons.
Once Hermes joined the game as the Intruder, Violet immediately added him to this group, as she felt she was able to trust him due to their pre-game alliance.
This alliance had an incredibly strong presence throughout the game. They started off at a disadvantage, Violet trapped in a blackmail by Treehouse member Draskk, and losing Celever in Week 2. However between Hermes effectively replacing Celever in the group, along with Violet winning the Legacy Advantage and the HOH, the power shifted quickly and a plan was devised to send Draskk home, which worked.
The Draskk eviction was the alliance's biggest collective move, as the week afterwords Violet was blindsided, and Mariano quit the week after that, leaving Lily and Hermes the only members left in the Final 6. Lily making a random flip to work with NP and evict Jade over TE (Hermes' plan) was the moment any former semblance of the Anti-Alliance died.
However Hermes, realizing Lily would ultimately be a finale goat and would lose to anyone, chose to keep her around instead of discard her, singlehandedly naming TE and then NP the final two members of the jury. As a result of this, despite little collaboration between Hermes and Lily, both ended up in the finale, ensuring one member of the Anti-Alliance would win the game. Hermes ultimately won in a sweeping 6-1 vote, only losing Violet's vote to Lily.