I'm not in any way related to Whatsapp. Whatsapp is a registered trademark of Whatsapp Inc.
CyanogenMod Theme Engine is required. Do NOT download if you don't know what it is!
To be honest, I got bored of the "Teal" accent of Whatsapp. For a change, I made the theme. It won't theme any other element but Whatsapp. It'll give your Whatsapp a Material Dark Feel.
It requires a custom ROM with CyanogenMod Theme Engine.
How to use:
*Apply through CM Theme Engine.
Only Whatsapp and nothing else! Do not download if you require more.
It'll get better with updates.