Buster Call

The Buster Call is an emergency order which calls five marine vice admirals and ten battleships from the marine headquarters to a single location. When a group is targeted by a power of national war class, nothing will remain. It can only be used with the permission of one of the marine's three admirals or the Fleet Admiral.

CP9 was granted one opportunity to use Buster Call against the Straw Hats by Admiral Aokiji.

The Buster Call is first mentioned in chapter 359, as Nico Robin explains why she left the Straw Hats.

Ohara
The Buster Call was seen in action 20 years ago (in 1502), accompanied by Vice-Admiral Kuzan (the current Admiral Aokiji), and Vice Admiral Sakazuki (the current Admiral Akainu). It is unknown who the other accompanying Vice-Admirals were; it is possible that Admiral Kizaru was one of them. Vice Admiral Jaguar D. Saul was orginally going to be one of the Vice Admirals present, but he deserted the Marines due to his oppostion of their Absolute Justice

The Buster Call managed to burn the whole island with a huge, simple cannon. Saul managed to destroy five Buster Call ships, and a sixth ship, a ship for refugees, was destroyed by Sakazuki.

After this, the World Government placed the blame on Robin for destroying these ships, in order to give her a bounty while keeping her real crime, the ability to read the language written on the Poneglyphs, secret.

Enies Lobby
20 years later, the Buster Call was summoned in a clumsy mistake made by Spandam. As he dragged Robin while running, he was angry that Luffy managed to catch up with him and Lucci. He tried to call the rest of the CP9 to find out what was going on, but he accidently pressed the Golden Den Den Mushi he had been given by Aokiji.

Scared, Robin tried to warn the whole island of Marines and World Government Agents to flee; Spandam, who believed that people should die in the name of Justice, struck Robin, stopping her.

This Buster Call was accompanied by five unamed Vice-Admirals; after the call, it took them 30 minutes to arrive at Enies Lobby.