If anything it was sealed away on Earth by Mebius' power,I don't know were it came from originally be it from space or from Juggler.
Ultraman Life - Every decision we choose not to make, comes back to haunt us later. So when you leave this world remember, those unmade decisions may have made you greater: TALK - Whenever
Basser was contained by Mebius at the ionosphere of the earth. Similarly, Taro contained Grand King underground. Basser was mealy 'sentenced' there, if you will, where he remained until, presumably, Juggler released him in a similar manner to that he did with Grand King. If your asking for his original origin, that hasn't been revealed as of yet.