When Commander Shepard blew Collector Station everyone were destroyed. Not one collector was able to survive except of one. He was deformated and drifted space for 2 decades before Oblivion Hunters picked up the body. They used human and drell DNA to craft him as first humanoid collector. he became one of hybrid hunters and later joined Dawn in his quest to kill Architect .
When he was picked up every scientist went looking on him. The used drell DNA to craft his humanoid appearence. He was placed back in shape and was sown back together. He was now something more. He was now more humanoid and had the intelligence of any wise man. For few weeks he was studying the English language and when he was adopted under the automatic translator. He was last of two species. Last Prothean because when he was under the Reaper Indoctrination process he proved to remember how he used to live on Omega as a rich Eezo miner and how he moved to local cluster to one base from where he saw the reapers coming. And last collector for obvious reasons.