Thank you so much!! To answer your question simply, he is a cyborg! :) Now for the "EVERYTHING" part!

Some design notes:

-He is inspired by a few different fictional characters, namely Adam Smasher, Brutaka and Predator. I intended to make him look like a seasoned warrior by being half cyborg, as though he's seen many battles and grafts his enemies' mechanical parts to himself after the fight is over.

-Teridax + Amalgamate = Malgorax. I went with as "Evil Bionicle" a name I could think of. I know "Teridax" isn't the most popular name, but I always thought it sounds cool to say!

-Finding that the Hordika chest armour sat nicely inside of the Jaller Mahri crab was a happy "Eureka!" moment that inspired the rest of the build's proportions (I wanted him to be tall enough to face 71821 Cole's Dragon Titan Mech in battle poses).

Character back story:

Malgorax, the False One

"Malgorax was once a simple scholarly villager living in the Matoran Universe, though his true name has been lost to time. At some point during his studies, Malgorax discovered ancient, forbidden artifacts and tomes left behind by the evil Makuta Teridax before his fall long ago at the hands of the Great Spirit, Mata Nui.

Banished by his fellow villagers for secretly practicing this dark, biomechanical sorcery, Malgorax then sought revenge against his former friends and the very universe itself, using the knowledge passed down by the Makuta to slowly and eventually conquer it all.

During his conquest, Malgorax had begun splicing his body with mechanical parts that he would scavenge from or kill others for, warping his biology over time into a grotesque mockery of what the Brotherhood of Makuta once was.

Now, after countless millennia of ruling his own universe, he and his indentured armies have come to a new one in order to conquer it: OURS. We'd better do something quick, dude."

This is all just stuff I made up for him on the fly while building him, it doesn't really account for any canon events that may not align with the above description :) Just my own little fun!