<span>The characterization technique which the author used in the excerpt is indirect characterization. With the use of this technique, readers can get to know the character through his actions and speech. There is no direct hint as description of appearance so readers themselves reveal character's personality.</span>
Johan August Strindberg, was a Swedish novelist, playwright, essayist and painter. Since childhood, Strindberg had a massive interest in religion, natural science, and photography. As a child, he always longed for a maternal figure due to her mother's bitterness and resentment of his intelligence. Later, after the death of her mother, his father married again with Emilia Charlotta Pettersson. This grew anger in Strindberg.
Therefore, circumstance what caused Strindberg to cut off from his family was due to his father's remarriage after his mother's death.
The detail that helps you illustrate the idea? is that the only question? I can answer that is there anything else you need me to answer in the paragraph?
First person
It takes a bit of reading into the passage to see what point of view it is, because there is little indication in the first paragraph. The first indication that it is written in first person is the use of "us" at the end of that first paragraph. Then, in the subsequent paragraphs the reader sees that the author uses "I" several times, indicating first person perspective.