The European syndicate was a syndicate on Europa.
Udai Taxim was part of the syndicate. When Fad and Jet Black of the ISSP was after Udai, a plan was made to kill or injure Jet Black, as Fad was being paid to work for the syndicate already. Coordinating with Fad, the plan was successful in that Jet lost his arm and left the ISSP. Later, Udai was caught, and decisions were made to change things so that the information Udai had about the syndicate was invalid.
In 2071, Udai sought the syndicate's help when the prison ship he was on was taken over and needed to escape. The syndicate refused to help, and informed him of the changes they made.
The syndicate member that Udai contacted in Black Dog Serenade was credited as "Syndicate Man" but was not shown on screen. He was voiced by Motomu Kiyokawa.