Nui-Kiru are Rahi created by Kakamu. They are small and yellow with long beaks. They were created to fight in the Battle of Zev's HQ but were never actually sent there. The Nui-Kiru were kept on board Darkmount, and their status after its destruction is unknown.
However, the Nui-Kiru live on as part of Serecio's army. When the Great Being was killed, his army was probably merged into other armies belonging to the GBs.