Read the lines and find the answer. Follow each one through to the end, but maybe not entirely.
My first is a dye, most commonly used.
My second is twentieth, in a cup.
My third is gloomy, shrouded in cloud.
My fourth periodically gets to a half century.
My fifth often stands for unity.
Crack them all, and put them together.
To find the answer, that perhaps I have left hither.
The title has been altered, and that should provide a major clue. (Apologies for not making this the title in the first place, when I crafted this last night. My mind certainly works better in the morning. :-P)