Sabemos que originalmente os Istari estavam encarnados e encarnados. Isso deu a eles corpos físicos vulneráveis à dor, etc.:
For with the consent of Eru they [the Valar] sent members of their own high order, but clad in bodies of as of Men, real and not feigned, but subject to the fears and pains and weariness of earth, able to hunger and thirst and be slain; though because of their noble spirits they did not die, and aged only by the cares and labours of many long years.
Unfinished Tales Part 4 Chapter II: "The Istari"
By 'incarnate' I mean [the Istari] were embodied in physical bodies capable of pain, and weariness, and of afflicting the spirit with physical fear, and of being 'killed', though supported by the angelic spirit they might endure long, and only show slowly the wearing of care and labour.
The Letters of J.R.R. Tolkien 156: To Robert Murray, SJ (Draft). 4 November 1954
Sabemos que os maiar não possuem necessariamente uma forma física, mas podem usá-lo como vestimenta. Isso implicaria que quando Gandalf, o Branco, retornasse a Valinor, e seu poder fosse restaurado (a perda de poder é discutida mais tarde), ele recuperaria sua forma espiritual e só assumiria a forma física se necessário.
A memória dos Istari do Reino Abençoado parece implicar que, embora incorporados como Homens, seu espírito Maiar (Fëa) permanece dentro. Isso faz com que eles anseiem por Valinor e se mantenham fiéis a sua tarefa (o que poderíamos ver da morte de Saruman).[T]heir shape comes of their knowledge of the visible World, rather than of the World itself; and they need it not, save only as we use raiment, and yet we may be naked and suffer no loss of our being.
The Silmarillion I Ainulindalë
Em conclusão, se Gandalf (Olorin) foi removido da Time, era simplesmente para Eru fortalecê-lo, e quando ele retornasse após derrotar Sauron voltaria a ser o Maiar Olorin.[T]hough they knew whence they came the memory of the Blessed Realm was to them a vision from afar off, for which (so long as they remained true to their mission) they yearned exceedingly. Thus by enduring of free will the pangs of exile and the deceits of Sauron they might redress the evils of that time.
Unfinished Tales Part 4 Chapter II: The Istari