For the record, 'mage' is not the normal translation of Magier in any sense. It's only an archaic, poetic word. It could describe, say, Merlin, if the King Arthur stories were told in old-fashioned language, but not anyone in a modern context or a Bible story.
A person who does magic, for example with a magic wand in a story, is a magician
, enchanter, wizard, etc.
The men who followed the star in the Bible story are the three wise men,
the three kings,
or the Magi
(pronounced /'mei-dschai/, like 'may gyrate'). You don't usually need the singular, but if you did, you could just say 'one of the wise men / three kings / Magi.'
The singular of 'magi' is 'magus,' but it's never used for the Bible characters, and only rarely in other contexts (for example, the title character in a novel).Siehe auch: magus, pl. magi - der Magus, der Magier, der ...