Grim Angels Deathwing coming up

I have finally assembled enough parts for me to build the 1st Company of my Spacemarine chapter "The Grim Angels". I will use the Black templar rules for them since I am a fan of Assault Cannons. I also settled on a Symbol which all my Terminators will field on their shoulder. It is not my design and I wonder how many of you will recognize it and tell me wehre it's from.
Since the weekend is coming up and I am stuck at home ill again I may actually get some work on it done. So far I habe removed the flesh of them and did the main conversion I needed to build the assault cannons arms.

edit: After drawing the logo several times on paper I decided to not paint it freehand on the shoulderpads. It's just too small(for me) to reproduce correctly. So I did some research and ordered decal transfer paper for laser jet printers. Also after consulting an article on BolS I purchased Micro-Sol and Micro-Set. I hope this will help to hide using details which I haven't done for years.