I got the idea to this MOC from a bit older MOC of mine, Toa Samol. These characters shared the same short and stubby appearance, so I decided to use a very similar design especially on the torso.
It's not a full clone though. The chest armour is more organic. I used Core Hunter's pec armour plate to give Onua a more muscular look. I also put the gear things to his back to remind of the gear function of the original set.
The hand design is a bit similar than Samol's, it's based on BCth's Pohatu's hands. I used the newish bar-plate pieces I got from Lighting Dragon Attack to make the angled fingers. They are all poseable, a feature that original Onua didn't have.
The legs are rather thin, but I wanted to preserve the robotic look of the old Mata limbs. The HF shell is rather boring piece choice, but work quite well as the "inverted" leg shape that Gali and Onua had. It also balances the color scheme nicely.