According to my fiction, the creators and original users of Anzer Pex were above and beyond humanity and before human concepts such as nations and flags and all that.
Thus, here is the flag of the first Anzer Pex speaking nation.

The top says "dena-ie'm" (pronounced like "deny-um") and the bottom says "tenese'm" (pronounced like "tehneh-sum"). I haven't quite worked out what these mean yet, but I'm thinking they'll be gerunds or possibly participles. "Dena-ie'm tenese'm" is, of course, the motto of this early Anzer Pex speaking country (also not defined yet).
The colors: gray, blue, green, brown, yellow, and red represent common experience and aspects of life. Stone, the sky, vegetation, soil, the sun, and blood/life (respectively) are most directly symbolized, but not the only ones.
The rhombus in the center holds blood/life (red) and the sun (yellow) together yet separate, implying that the sun contributes in sustaining life, but does not give life itself.