Davis is a character mentioned in the Codex entry.
Davis was a researcher presumably (speculation) during the Orokin Era, working in a facility developing metallic creatures, presumably Warframes. At some point during his work, he developed a theory regarding the creatures he and others were working on and the victims of the Zariman. Believing that no one else would ever have believed him, he seemingly released the creature and allowed it to chase him and an unnamed colleague (who narrates the Codex entry) to a cell.
The creature mysteriously went calm after approaching the cell. His experiment seemingly successful, Davis tells his unnamed colleague that "This is where they keep them. The ones from the Zariman", and that because of this success both of them would receive "big, fat promotions."
What happened to Davis after this is unknown as this is the only time he is mentioned in the codex.