Demon swordsman and Tank mech (working progress)

so been doing some sketches for certain characters and maybe some advice or help be nice while working on them. based on the original sketches I did as a kid and wanting to redesign them.

One of the characters I drew was inspired by General Grievous from the original clone wars animated movie, and wanting it to look somewhat like a demonic swordsman with multi arms. So for the idea for him be to change the swords or redesign them as some sort of trophies he claimed from previous battles he won and drew some sort of tank mech and gave it a tail (not sure why lol) but for the new version will look better without it. So will work on them more like the others I will upload shortly.

Tank robot

Demon swordsman

Sketches of the designs I've done so far.