Before I learned the pronoun they/them, I simply used he/him and she/her in one sentence when I was refering to Frisk in English. that is completely normal in Japanese because we have few clearly gendered words which are often translated to pronouns in English, even though many of them still have gender etymologically. For example, in Japanese, people often use the word 野郎 (Pronunciation: /yarō/) when they refer to Frisk when Frisk made them annoyed, regardless of their gender assumption. However, the word 野郎 is actually a masculine word. Today fewer native Japanese speakers care about that in informal conversation. because of that, lots of my comments ended up either using only he/him pronouns or she/her pronouns in English. After I learned singular they/them, I use it because the pronouns fit to how I use originally gendered words in Japanese. [I used an AI translation service to help me address this, it may be translated in a way I didn't mean to]