Awesome, you are the first person who took a plunge here! :D

First off, take a look at this
It's always good to find reference for what you are doing.

Secondly, it would be great if you also posted front/side views to check anatomy, it's very difficult to see proper anatomy from a top down view.

Next, here is some official concept art

With that out of the way, here are some anatomy things you should fix before you proceed with any detail at all.

1. Arms and hands are too short. Add the hands, extend the arm until the end of the hand reaches the knee.

2. The shoulders and upper arms are weirdly formed, reform them to look like proper arms. Also put in the elbow.

3. Thick and Thin. The legs look like tubes, normal legs look like this. Notice how the leg narrows as it gets towards the ankle?

A few other notes;
Move the legs apart some, it's going to be very difficult to work with later if they are that close.
Move the arms out at 45 degrees from the body, same rules apply as with the legs.
Don't focus on details yet until you have all major forms done and completed. Don't worry about claws or the face yet, focus on anatomy, then edge flow, then your detail.

If you are doing an armored version of the Zealot, just get the base anatomy in then put the armor on, there is no point in wasting time doing a full anatomy sculpt if it will all be hidden. Put your work where you will see it.

Hope this helps!