The flag of Upper Blemmyes
The background is Upper Blemmyes green, but many simply consider it Blemmyes green. The 2 pointy stripes in the lower corners are probably just that, 2 pointy stripes. Why they are there is unknown, perhaps they thought it looked nice. The darker brown stripe gives the flag depth, although it is unknown if that was intended or not. The stripe perhaps refers to the Blemmyes, a peacefull tribe (of dark / brown skinned people) living near the Meroe.
The flag of Upper Blemmyes under Chra Ptolemey
It should come as no surprise that Chra Ptolemey added a thin bordor in their green color around the flag, like they always do.