Diablo Immortal

Hi. Could you please let me know why character in Diablo Immortal lights orange? What is the purpose?

Most likely to show that your attack has hit the intended target especially if you are fighting within a mob.
Most people no longer even notice it, or they do not care about it. In D4 we will be able to turn it off.

But I mean it lights permanently. Is it connected somehow with the clans? Dark clan stages?

could you post a picture? are you seeing your character name orange? If you are an immortal, your name will be color’d differently.