"... When I was escorting Miss Hope to the caverns, she asked me about what I was. She said I reminded her of a people who were created long ago and have since ceased to exist."

Zenyatta gives a sigh that is uncharacteristically tired sounding.

"I wished to know more, but much information about them have been lost or hidden. And while Miss Hope did not say it concretely, it seems they were involved in war. And what she has heard, unpleasant." Singular, plural, Zenyatta can't say. Hope didn't know the details (or didn't divulge them).