The Real Doer is God.

Kenopaniṣhad states:

यद्वचनभ्युदितम् येन वागभ्युद्यते। 1.4

“Brahman cannot be described by the voice. By its inspiration, the voice gets the power to speak.”

यन्मानस न मनुते येनाहुर्मनो मतम्।1.5

“Brahman cannot be understood by the mind and intellect. By its power, the mind and intellect work.”

याचचक्षुषा न पश्यति येन चक्षूंषि पश्यति। 1.6

“Brahman cannot be seen with the eyes. By its inspiration, the eyes see.”

यच्छ्रोत्या न शृणोति येन श्रोत्रमिदं श्रुतं। 1.7

“Brahman cannot be heard with the ears. By its power, the ears hear.”

येत् प्राणान् न प्रयनिति येन प्राणः प्रणीयते 1.8

“Brahman cannot be energized by the life airs. By its inspiration, the life airs function.”

शरीरवाङ्मनोभिर्यत्कर्म प्रारभते नरः।
न्याय्यं वा विपरीतं वा पञ्चैते तस्य हेतवः।।18.15।।

तत्रैवं सति कर्तारमात्मानं केवलं तु यः।
पश्यत्यकृतबुद्धित्वान्न स पश्यति दुर्मतिः।।18.16।।

These five are the contributory factors for whatever action is performed, whether proper or improper, with body, speech, or mind. Those who do not understand this regard the soul as the only doer. With their impure intellects they cannot see things as they are.

The three kinds of actions
 
कायिक - performed with the body
वाचिक - performed by speech
मानसिक - performed by the mind

Due to the ego, we think of ourselves as the doers of our actions. “I achieved this.” “I accomplished that.” “I will do this.”

These are statements we make under the illusion of being the doer. Shree Krishna’s purpose in revealing this knowledge is to annihilate the soul’s pride of doership. Thus, he states that those who see the soul only as the contributory factor for action do not see

things as they truly are. If the soul were not granted a body by God, it could not have done anything at all. Further, if the body were not energized by God, it could have still done nothing.

This does not mean that the soul has no role in performing karmas. It is like the driver in the car, who controls the steering wheel of the car and decides where to turn it and at what speed to drive. Similarly, the soul too governs the actions of the body, mind,

and intellect, but it should not claim credit for any action for itself. If we see ourselves to be the sole cause of action, then we want to be the enjoyers of our actions as well.

But when we free ourselves from the pride of doership and ascribe the credit of our efforts to the grace of God and the tools provided by him, then we also realize that we are not the enjoyers of our actions and all actions are meant for his pleasure.