Bart Torgal

Bart Torgal was the heir to Torgal Corp, and the only legitimate son of Paul Torgal. Bart was a beneficiary of advanced learning techniques, having cerebral implants and learning farming through 'Digitraining', using this knowledge he kept the three Degasi survivors alive by growing food.

Bart discovered that the survivors were infected with an alien bacteria and attempted to find a cure. Marguerit Maida would bring Bart samples to see how they reacted to the bacteria. However, these were often not of much use as Marguerit tended to either severely injure, or use Transfuser serums on the creatures, making them unsuitable for testing.

Bart's last known location was the western observatory on the Floating Island, to which he fled after the destruction of the Deep Grand Reef base. He made a final log, detailing the effects of Kharaa on him, and notes that he will join Marguerit and Paul soon, implying their demise.

Bart provides the voiceover for the official cinematic trailer of Subnautica, a slightly edited version of his third and final log "Return From the Deep". A brief snapshot of his life after Paul and Marguerit's demise is also shown.

Post Degasi Crash
Eventually after Marguerit and Paul's deaths, it is shown in the cinematic trailer that Bart survived for quite some time, able to build himself a base in what appears to be the Safe Shallows or the Crash Zone, a Seamoth, as well as gather several pieces of lab equipment. However, it is also shown that he eventually abandons his base, where he eventually succumbs to Kharaa.

Personality
Bart has an interest in plants, as noted by his father, and having gained Cerebal Implants. Bart had a great interest in the wildlife of Planet 4546B, often disapproving of Marguerit's methods; in one log saying "what's the point in surviving here if we have to kill everything that makes it so wonderful?". After the destruction of the Deep Grand Reef Seabase, he seems to be accepting of his fate, and unfazed by the death of his father and friend.

Paul Torgal
Despite Paul being his father, Bart does not seem particularly close to him. It can be noted, that Paul seems overprotective over his son, however, this may be due to the fact that they are on an alien world, and Paul fearing for his safety. It can be noted, that Bart can be upset and/or angry when Paul and Maida fight, and usually attempts to stay neutral. Ultimately, however, Bart realises that Maida was wrong and that his father was right to not want to go deeper.

Marguerit Maida
Bart and Maida are genuinely friendly to one another, with Maida bringing Bart specimens for him to study. Bart is also fascinated with what Maida will do to ensure their survival. However, he does not agree with some of Maida's methods of getting creatures for him to study, and can get upset when she severely injures them or injects them with Transfuser serums. Despite this, he has a high amount of respect for Maida, which Maida returns to him. Ultimately, however, Bart realises that Maida was wrong and that his father was right to not want to go deeper.

Trivia

 * Bart's original name was Baat, but was changed in later development to Bart.