The Client is a young Israeli man with pale skin, green eyes and short dark brown hair . He's commonly seen wearing a silver blazer, alongside a black tie and white shirt. He also wears a black belt, with a silver buckle and black trousers.
Initially only the Client's voice could be heard through a small speaker, talking to Ze'ev. The client had hired Ze'ev and his gang to carry out Project Nexus in a bid to sink a couple of islands, through the use of earthquakes. After Ze'ev fails to carry out this plot, the Client supposedly shoots him dead during the finale of Season 1.
The Client returns during the second season as the main antagonist, where it's revealed that he's an additional personality of Robbie Klein, also known as Sherry, who is displayed as a crazy and demonic genius. Throughout this season, he attempted to spread a virus at an upcoming peace conference.
Making a deal with Ozzie, The client planned to get him to coax Foley into bombing the virus so that he could go on with his plot. Also in Season 2 he appears to have freed Robbie Klein from prison, with Robbie then working alongside him. Later he attempts to kill Ellali and Iftach due to the fact that they carried antibodies in their blood that would fight against the virus, with Ellali drinking water from the Hole and the surgery implant that Iftach had gotten.
Firstly he sent both Judy Goren and Jeremy in an attempt to poison both Ellali and Iftach, with Jeremy posing as a nurse at Iftach's sanatorium and Judy going to see Ellali and her son to make up for what she had done previously. After his attempts had failed, The client released Arik from prison and had him go after both Ellali and Iftach, trying to kill them, however this plan failed and Team Galapagos succeeded in foiling his plan.