Answer:
I fly, yet I have no wings. I cry, yet I have no eyes. Darkness follows me. Lower light I never see.
I run around the city, but I never move.
Voiceless it cries, wingless flutters, toothless bites, mouthless mutters.
I'm not man's best friend, I'm their enemy, I can mark your end, yet you do not see me, I am very small, but very tough, If you have me, then you have it rough.
Some try to hide, some try to cheat. But time will show, we always will meet. Try as you might, to guess my name. I promise you'll know, when you I do claim.
If itβs information you seek, come and see me. If itβs pairs of letters you need, I have consecutively three. What am I?