Danis (surname not recorded) was an employee of Mabius Intersystems, and in 3730 ELC he was known to be acting as part of the flight crew aboard one of their long-haul cargo ships, specifically the MICS Maidesvale.
For at least some of that tour of duty he was the romantic partner of a young Euryce Eilentes.
Danis and Euryce Eilentes were already in a relationship when Euryce was promoted into the role of Flight Operations Assistant (FOA) aboard the Maidesvale, with the intention of the ship's captain being that she would replace the current FOA, Mister Hakuri, when he left the company. Although initially sharing Euryce's enthusiasm and joy at the promotion, Danis soon became cooler and more cynical as he began to suspect that Euryce and Hakuri were having an affair. There was nothing at all to indicate this was the case, and Euryce found this previously unseen jealous side of Danis to be very off-putting. This culminated in a three-way confrontation in the ship's commissary, during which Danis punched Hakuri in front of multiple witnesses. Danis and Euryce separated very publicly during that incident (→TRD).
After Euryce's promotion, Danis commented on her being closer to her goal of attaining a command. It is not clear why Euryce later decided against being in command of a starship as a career goal, but it seems likely that she associated that idea with Danis and therefore became less enamoured of it after their acrimonious separation (→TRD).
At the time of those events, Danis and Euryce were on shift patterns which did not match. While not excusing anything, particularly Danis' possessiveness, the reduced opportunity for them to spend time together may well have exacerbated his jealous response to Euryce being around other men (→TRD).
While aboard the Maidesvale Danis saved money by giving over most of his allocated storage space to freeze-dried food, instead of the more usual choice of clothing and personal accessories. This meant he did not need to buy so much food from the company's expensive onboard commissary, but he did have to alternate between only two T-shirts when off duty. He considered First Officer Esmere Faitana to be a "ball-buster", but this may have had more to do with his own work ethic than the actual personal traits exhibited by the XO (→TRD).