Elias Theodorou

Former UFC fighter Elias Theodorou died Sunday following a battle with cancer. He was only 34 years old. Theodorou had been courageously fighting stage 4 liver cancer ... but chose to share the diagnosis with only select people who were close to him. Elias -- an outgoing and personable dude…

Elias Theodorou just made history as the first UFC fighter to work as a "ring boy" ... and after killin' it in his debut, says he's got HUGE plans for the concept!! We spoke to Elias after last weekend's fight card for Invicta FC (an all-women's MMA promotion) ... where he strutted around the cage…