Here is Tristan's family tree:

The interesting entry here is obviously ROE
VAN. Who is Roe Van? While Tristan was still in the womb, he had a twin
brother. Tristan absorbed his brother, so the name that was going to go
to him just went into Tristan's name; that is why he has two first
names and two last names.
However, there is now evidence that Roe Van
is alive. He appears to hang around UAF (or wherever Tristan is), and
typically causes mischief.
Roe Van Evidence Images:

"Roe Van" written in the frost on Tristan's Car. Clearly stealth is not Roe Van's forte.

"Roe Van" written in early snow at UAF.

"Roe Van" Written on a table near the laundry room. As evidenced by the
"Van," Roe Van has been working on his handwriting abilities.

Even when winter was just about over, Roe Van managed to snatch
Tristan's ice scraper from my hand and use it to graffiti a quick
signature on the window of his car.

Although this photo has all the signs of a Roe Van sighting, it lacks his signature.
This can serve as official evidence that Roe Van knows x86 Assembly, possibly from the DOS era considering the fact that
he still uses Intel String Instructions.