The Sirsal Bankers are two bankers who run the bank on Lunar Isle. They are also two of the only three men on the island. (The third is the pirate-banker 'Bird's-Eye' Jack.) Like the women of the Moon Clan, the two bankers float behind the bank's counter.
Formerly, players would need a Seal of passage to bank with them, and if they try to bank without one, they will be sent off the island, to Rellekka.
However, after completing Dream Mentor, players can bank with 'Bird's-Eye' Jack without the seal. Talk to 'Bird's-Eye' Jack, and select "Using the bank."
This is the closest bank to the Astral altar and is used by players when crafting Astral runes.