Dak Vesser was a Force-sensitive Human who attended both the Jedi Enclave and Sith Academy before finding neither of them fulfilling. He was friends with Juhani while at the Enclave, and later persuaded by his former friend to leave the Academy on Korriban.
In Star Wars: Knights of the Old Republic, Revan met Dak while travelling with Juhani. Dak answered a few questions of Revan's before leaving the Valley of the Dark Lords. Revan later saw him in the cantina, and had the choice of killing him (dark side points) or merely asking him how he knew Juhani and leaving.