Raiden

"I'm worried about this Collector stuff, I've become attached to my ship, but more to my crew...I trust you commanders."

- Raiden on the Ulyssey

Raiden is a volus who used to work for the Volus Pirate Associates, a group who would raid ships and steal, often killing those aboard or enslaving them to work or sell to others. In the process of being in the group Raiden secretly founded an abandoned vessel that was named "Ulyssey", it belonged to an unknown faction, presumed Alliance or Asari.

In time, Raiden crash landed on Ollahmi, a desert planet belonging to their long-lived rivals, the Bartarians. Raiden and his fellow associates fought off the Batarians enough to were both were waiting for each other to make the shots to commence war. Moments before all of the setup Bahamut slammed into the ground, causing a massive explosion which erupted most of the ground on Ollahmi.

Commander Ebrown and Solaris emerged from the Bahamut a day later to find the war on its first stances, entering the Bartarian camp they found Young and met up with Raiden, who had already considered himself an outcast from the Volus Pirate Associates.

Ebrown and Solaris agreed to help Raiden get the radar working, which could remotely signal a shuttle to save them and help them board the Ulyssey, Raiden knew that if he would have to get off Ollahmi he would have to get the Ulyssey, which required the working Radar, for a price he would have to give his ship in the hands of the commanders and Young. Raiden agreed, saying he was also in for the ride too. Medge fixed the radar, and all of the group boarded the shuttle, entering the new ship they call Ulyssey.

Raiden is required to wear a suit for his entire life, some alien races in the galaxy share the same pain such as Quarians. Raiden breathes a substance that is highly toxic to 95% of all life besides Volus, his race is from a high-polluted CO2 atmosphere, his suit is hooked up to trasmit CO2 into his body so he may breathe.

Death

Raiden offered to help the commander retrieve a demolitions expert and his resources, on his way to get it he was pinned down by snipers and shot them off, saying that he would make it.

The mysterious blue-suited man walked out, and fired a single shot into Raidens helmet, penetrating his CO2 tubes, refusing to let him breathe as he died a slow and painful death by suffocation.

Before Raiden died, he mentioned that "Mona and I had something that could never have lasted" hinting both had a strong relationship towards eachother, it was later shown at his Funeral, Mona was extremely devastated with his death.

Raiden could've been saved by the Lazarus project, but just like Mordin, there was not enough material to even fix close to what condition he was in.