Lumas
Lumas was a Caatati. Most of his species, natives of the Delta Quadrant, had been assimilated by the Borg sometime before the year 2374. He and a few thousand survivors managed to escape the calamity on thirty ships, but with nothing, and were forced to roam the quadrant as beggars, starving and destitute. 

In 2374, he and his fellow survivors encountered the  and asked its commanding officer, Captain Kathryn Janeway, for supplies. Janeway was able to spare some supplies, but was unable to give all that he wanted. After coming aboard the Voyager and attempting to get more by trying to make Janeway feel guilty for not giving them more, even though she could not, he saw Seven of Nine in a corridor. On finding out she was a former Borg drone, he tried to attack her, and had to be restrained by Tuvok.

When Voyagers warp core went critical and had to be ejected, the Caatati stole it when it did not explode. Lumas used their possession of it, along with surrounding the Voyager with nearly all of the thirty ships they had, to attempt to force Captain Janeway to surrender all of Voyagers supplies and weapons to them. He also demanded Seven of Nine, whom many of them wanted to make sport of in revenge for what the Borg did to them. The crisis was resolved when Seven built an energy matrix for them, which produced thorium isotopes. Caatati technology ran on thorium; thus, with this matrix, and schematics on how to make more of them, they could thus create all the supplies they needed. ()

Background information
Lumas was played by actor Alan Altshuld who filmed his scenes on Monday  and Tuesday  on Paramount Stage 9. His name comes from the script.

Since Lumas wasn't named in the episode and his first meeting with Voyager is not shown, a viewer could make the mistake of assuming that he is the same character as Rahmin, due to the identical Caatati makeup. The Star Trek: Voyager Companion also confuses the two characters, saying "Rahmin is outraged when he sees that the crew includes an ex-Borg".

His costume from this episode was later sold off on the It's A Wrap! sale and auction on eBay. 

The ization of  gives his full name as Agron Lumas. He had two daughters named Finaea and Anyelot.

External link 
 

de: Lumas
Caatati