Hayate is one of Konoha's special jounins. He's also the one who was judging the chuunin exam's third stage preliminary matches. He is said to be one of the most talented shinobi of the leaf, but his (apparently) chronic sickness seems to have made him weak. He has bags under his eyes and doesn't look healthy at all.
When he was accidentally eavesdropping on Baki and Kabuto, he found out about the secretly made treaty between the Hidden Sand & Sound Village, and the plan to attack the Leaf Village. He is then noticed by Kabuto and gets into a fight with Baki. Although Baki praises Hayate for his skills at such a young age, his Dance of the Crescent moon is easily countered. And Hayate is killed, giving his life for the Leaf.