The illusion is present in the form of ‘I’.+

Rig Veda: ~ 'Prajnanam Brahma'- Consciousness is the ultimate reality or Brahman or God in truth.

Do not accept any other truth other than the consciousness. Consciousness is the ultimate truth, Nothing is real but consciousness. Nothing Matters but realize the ultimate truth. Consciousness is everywhere and in everything. Let these words be inscribed in your subconscious. Consciousness is ever nondual. 

Limiting consciousness to your physical body is an error. your physical body appeared along with the universe in the waking state (duality)and disappears along with the universe as the Soul in deep sleep (nonduality).

The same way as the dream body appeared along with the dream universe and disappeared along with the dream universe.

Seeker has to take the waking state and dream as a whole. You are not separate from the universe because you are part and parcel of the illusory universe, which appears as waking or dream (duality)and disappears as deep sleep (nonduality).

Only in ignorance, you feel you are a separate individual apart from the universe and the universe existed prior to you, and you are born within the universe.

Only in ignorance, you feel the universe in which you exist is a reality.

Until you hold the Self as yourself you will remain in ignorance of the Soul, which is the real Self. 

Remember:~

The illusion is present in the form of ‘I’. 'I'  is present in the form of  mind. Mind is present in the form of universe. 

The universe appears as waking or dream (duality) and disappears as deep sleep (nonduality).   

The three states are one in essence and that essence is consciousness. Consciousness itself is the Soul the Self. On the standpoint of the Soul, the Self the three states are illusory.

Experiencing the birth, life, death, and the world is a reality within the illusion (waking or universe) 

You are the illusory self (ego), within the illusory experience (waking) thus whatever your experience is bound to an illusion.

The illusion is created, and sustained, and finally dissolves as consciousness Since there is no second thing other than consciousness;  consciousness itself is the ultimate truth or Brahman or God in truth.   

The one who has realized this truth for him this illusion is passing show because he is fully aware of the fact that his body, his ego and his experience of the world be consciousness. 

Practical people's approach is more practical, and they are stuck with the reality of the practical life within the practical world, they take it as real whereas Gnani sees his body his ego and his experience of the world as consciousness.:~  Santthosh Kumaar