The difference between liquid soap and liquid laundry was their active ingredients and starting materials. The active substance of the soap was mainly soap base, and its starting material came from regenerative plants. The active substance of the laundry liquid was mainly coconut acid dialcoholamid (a surface active agent), and its starting material was crude oil. In addition, the soap liquid contained a soap-based active ingredient, which was similar to grease in structure. It was more effective in removing grease stains, and it was easy to separate from the fabric, improving its bleachability. On the other hand, the laundry liquids mostly used non-ion-type surface active agents, which were close to neutral, mild to the skin, and degraded faster after being discharged into the natural world. In addition, the formula structure and implementation standards of soap and laundry liquid were also different. In general, soap was superior to laundry liquids in terms of gentleness, grease removal ability, and bleachability.
Toge Inumaki is important too. His special cursed speech ability makes him stand out. Also, the principal of the school, Masamichi Yaga, is likely to be important as he is in a position of authority and has an influence on Gojo and the other students. There could be other characters like the members of different clans that also play roles in the complex web of the story.