So I didn't have a background on my laptop, I drew myself one.
This is an old character of mine, odd backstory.

Long story short, the things on his arms are an artificial parasite made from the remains of his ancestors, each generation of his family receives this parasite upon birth. It grants enhanced physical strength, and is intended as a weapon of war.

The parasite is evil-ish (though it wasn't intended to be), and speaks to him. He's not necessarily evil, but is easily influenced by the parasite.

His arms can (and must) consume organisms for both the host and the parasite to live.

Enough boring you with the silly antics of my 12 year old self... I was weird back then.