Yes, Goku does realize he killed his adoptive grandfather, Gohan.
The original question is about whether Goku is aware that he was responsible for his adoptive grandfather's, Grandpa Gohan, death. Here is more detail:
Goku, in his Great Ape form as a young boy, accidentally stepped on and killed Grandpa Gohan. This was before he met Bulma and started his adventures in Dragon Ball. As a child, Goku was unaware of this due to amnesia caused by a head injury, losing all memories of how Gohan died. However, during the Saiyan Saga in *Dragon Ball Z*, when Goku transforms into a Great Ape while fighting Vegeta, the traumatic memory resurfaces.
Here's a breakdown:
- Initial Amnesia: Goku had no memory of killing Grandpa Gohan.
- Saiyan Transformation: The transformation into the Great Ape form during the fight with Vegeta triggered a flashback.
- Realization: In his Great Ape transformation, Goku finally remembers what happened and the truth of his grandfather’s death.
- Guilt: Goku expresses deep remorse for killing his grandfather.
The reference text explicitly states:
In Dragon Ball Z, when Goku was battling Vegeta as he transforms into a Great Ape, Goku finally realizes that he killed Grandpa Gohan when he was little and would apologize to his grandfather.
Therefore, the answer is definitively yes; Goku becomes aware that he caused the death of Grandpa Gohan. He was not always aware, but he did realize it.
