I heard from someone that the Shlah hakadosh was a decendant from a certain group of levi'im in the beit hamikdash called Sgan Levi. I was wondering how can I verify that fact, and once I can verify it, what exactly were the tasks of a sgan levi, and is it possible to know if they came from gershon, kahat, or merrari?

Asaf was appointed the chief levite and his first assistant (mishnahu) was apparently also from the same family. If I read correctly then the mishneh to the head of the house of levite would be from meriri. The term segan, which is the same as mishneh, is used for the segan cohen gadol in the the Mishneh but I don't recall seeing it used for the levi.

Aryeh Shore
Aryeh Shore

I was waiting to meet someone in the Gra shul who I knew was a direct decedent from the Shlah hakadosh. He said that in his faimily tradition the Shlah hakadosh was a Sagan Levi from Kahat.

off topic but i davened in the Gra shul once - nice neighborhood - shareei chesed