Radagast skickades för att utföra en liknande roll som Gandalf, men blev för distraherad av fåglarna och djuren i Middle Earth. Från Oavslutade Tales :
Radagast, the fourth, became enamoured of the many beasts and birds that dwelt in Middle-earth, and forsook Elves and Men, and spent his days among the wild creatures.
De två kvarvarande Istari var Alatar och Pallando, Blue Wizards. I Oavslutade Tales nämns det
Whether they remained in the East, pursuing there the purposes for which they were sent; or perished; or as some hold were ensnared by Sauron and became his servants, is not not known.
I Brev 211 expanderar Tolkien lite mer här:
I think they went as emissaries to distant regions, East and South, far out of Numenorean range: missionaries to enemy-occupied lands, as it were. What success they had I do not know; but I fear that they failed, as Saruman did, though doubtless in different ways; and I suspect they were founders or beginners of secret cults and 'magic' traditions that outlasted the fall of Sauron.
I Medelvärldens folk skrev Tolkien senare att de kanske har varit mer framgångsrika än annars trodde, så hans tankar om dessa två kan ha förändrats under åren:
The 'other two' came much earlier, at the same time probably as Glorfindel, when matters became very dangerous in the Second Age. Glorfindel was sent to aid Elrond and was (though not yet said) pre-eminent in the war in Eriador. But the other two Istari were sent for a different purpose. Morinehtar and Rómestámo. Darkness-slayer and East-helper. Their task was to circumvent Sauron: to bring help to the few tribes of Men that had rebelled from Melkor-worship, to stir up rebellion and after his first fall to search out his hiding (in which they failed) and to cause [? dissension and disarray] among the dark East. They must have had very great influence on the history of the Second Age and Third Age in weakening and disarraying the forces of East who would both in the Second Age and Third Age otherwise have outnumbered the West.
Det är den utsträckning vi känner till Blue Wizards.