The Wild Geese are a group of mercenaries that were hired as soldiers after a Millennium attack on the Hellsing Organization's headquarters left the organization severely short-handed.
The leader of the Wild Geese is Pip Bernadotte, a womanizing Frenchman who loves to tease Seras Victoria. Its members are remarkably mixed in ethnicity, age, and background. Most of the members were equipped with either MP5s, M4A1 carbines or AK-74s along with automatic grenade launchers and machine guns. Upon joining the Hellsing Organization, they were given silver ammunition for their weapons.
Though highly skilled, they are no match in a close fight against the Millennium forces and rely on measures like remote-detonated mines to combat them. When Millennium broke through most of their members were massacred.
The Wild Geese were hired by the Hellsing Organization in order to maintain security of their headquarters. Then they were introduced to Seras Victoria whom at first they didn't believe to be a vampire until Seras gave Pip a little taste of her strength which proved to them all that vampires were very real.
During Millennium's invasion in London, Zorin Blitz was given charge to destroy Hellsing headquarters but they came under attack by Seras, resulting in losing half their forces and most of their heavy weaponry with the Wild Geese destroying their ground forces with mines, claymores and a lot of firepower. Zorin however used her powers to create an illusion against the Wild Geese, that Seras was later able to snap them out of. However at that point it was already too late as Millennium forces had stormed the mansion and slaughtered the majority of them. The remaining members barricaded themselves within the mansion and luckily Seras arrived in time to save them, massacring the SS troopers with Zorin. Alas, she ran out of ammo for her Harkonnen and she was no match against Zorin in hand-to-hand combat. Zorin used an illusion to weaken Seras. Pip eventually rescued Seras but was killed himself by Zorin. When Seras drank Pip's blood she was able to destroy reinforcing Millennium members along with Zorin. Two (in the OVA, the rest are wounded resting behind if not dead) or Three (in the manga) of the remaining Wild Geese members bids farewell to Seras as she heads towards London.
- The name, Wild Geese, is believed to be derived from a movie during the seventies that shared the name and was about a group of mercenaries in Africa. This is incorrect, and is a reference instead to The Wild Geese, the Irish who left Ireland following the Treaty of Limerick. Pip being French, it's possibly an homage, since it was the Wild Geese serving France who finally broke the back of the English army at the Battle of Fontenoy in 1745, (according to some accounts taking the colors of England's Coldstream Regiment of Foot Guards). (Which would place their entry after the dissolution of the 'official' French Irish units. However, many organizations of predominately Irish mercenaries are known to refer to themselves as the "Wild Geese", particularly those dating back to the 18th and 19th century.)
- It is unknown what happened to the remaining Wild Geese members after Zorin's attack. It is possible that they may have continued to be employed by Hellsing. It's also not unlikely that the survivors may have continued working as the Wild Geese with a new commander, or, since Zorin's attack left them with only a fraction of the manpower they had before, they could have disbanded.
- "Wild Geese" is also the name of the Hellsing Ultimate OVA production committee (this is why the name appears in the credits).