Visser One is the highest rank in the Yeerk military hierarchy. The Yeerk holding this position is answerable only to the Council of Thirteen.

There have been two known holders of the rank of Visser One:

• Edriss 562, in the host body of Marco's mother Eva.
• Esplin 9466, the previous Visser Three, who is promoted to the rank after Edriss 562 is killed.