Here's a Space Marine and there's a Space Marine and there's a Space Mar... errrr. He's not looking so hot chief, I think we'd better break out the Covid swobs just to be sure!
Okay, so I just felt like drawing a few Space Marines to prove I could. Even John Blanche who is hailed as the God of Art for everything that is Warhammer said that Space Marines are one of the hardest things to draw. I totally get that. We are used to training as artists to draw human anatomy and then suddenly we have to throw it up to over 8ft and slap Power Armour on it and make it look great in action?!?! That is tough. No wonder most people's first attempts look like they've been made out of the same balloons that clowns use to make you a dog at your birthday party. That's why proving you can draw such challenges is a must.
Here I wanted to draw a Primaris Space Marine who's design is already standardised but to do him in a great dynamic pose. I also did the side view doodle. Not having the room to do the entire turnaround which would have been great, but I wanted to show that I had given thought to that part of the process.
Secondly I wanted to create a concept piece for a new type of Marine proving my skills at concept working while maintaining the core aesthetics.
Thirdly, I wanted to show a Chaos Marine as well because... well, my heart has always belonged to Nurgle. 
Transition between sketches. Here I take ideas from an early Terminator design, transpose them on to a true-scale Space Marine and bring it up to date in V1 (but I did use the MKVI 'Beaky' helmet because it fits so well. Then I moved forwards, taking my favourite and key elements into V2 while trying to bring the marine more into focus. V3 Keeps all the fundamental and recognisable shapes but is more recognisable as a modern Space marine. You can see on the full sheet how the marine continues.
Desolation Marines carry heavy armour and heavy weapons... but what if they only had to carry one of those. Since they are such a specialised unit it seems that their armour should be more integrated with their weaponry. That is where my basic desire to create an armour with built in weaponry comes from.
On the right, you can see an idea for a (Ultramarines) Tyranid Hunter Armour. Shaped with the same shell like texture/pattern as the Horde themselves. Be it forged in steel or cut from bone. A Tyranid Hunter should be able to hide withing the lair of his prey. Number 16 also has aspects of this design. If you're wondering why I have them all numbered - it's so you can tell in which order I created them in.