A quick 'net search revealed that the name "Yahseph" appears to be a contrived version of the name "Joseph" (from the Hebrew "Yosef") and is used by a religious doomsday group calling themselves "The House of Yahweh", in Abeline, Texas.
Here's what ReligiousTolerance.org has to say about the House of Yahweh:
http://www.religioustolerance.org/dc_house.htm
Heheh. They also believe that Satan is a female. They got at least one thing right. ;)
-- Nanaea