During the Story
When the Exile arrives on Onderon to find Jedi Master Kavar, who is helping Vaklu's rival, Queen Talia, Tobin greets the Ebon Hawk with a small fleet of Onderon fighters. This forces the Exile to make a landing on Dxun and to get assistance from Mandalore to reach Iziz, the capital of Onderon. While the Exile was trapped on Dxun, Tobin ordered scouts to patrol the jungle moon for the Exile and the Ebon Hawk, and wanted them to destroy the ship. The Mandalorians and the Exile find the scouts, however, and Tobin's operation is unsuccessful.
When the Exile arrives on Onderon, they find the city of Iziz on the brink of civil war. The fight between the Ebon Hawk and the Onderon military had triggered a battle with the Republic. More and more people supported Vaklu in favor of preserving the culture of Onderon. When the Exile finally gets the attention of Kavar and meets him in the cantina, Tobin and some of his soldiers ambush them. If the Exile supports Vaklu, Tobin apologizes, saying he has to keep up appearances, and orders his soldiers to continue to attack in order not to arouse suspicion.
The Exile is summoned to Onderon again after a time, and learns about Vaklu's alliance with the Sith. When the Exile arrives, they find Iziz has been thrown into full-scale war, and if they supported Vaklu, he comes to greet them and asks that they fight off the Royalist soldiers. If they sided with Talia, Vaklu's soldiers are hostile to them. No matter the outcome, Tobin is apparently killed by a drexl beast, which the Sith controlling it on Dxun have lost control of. Darth Traya sees that his wounds are not mortal, and uses the colonel in her own schemes against Darth Nihilus, sending him to his flagship to tell him about a false Jedi academy on Telos, which would apparently destroy him.
When Darth Nihilus' forces attack Telos, the Exile boards the Ravager, and finds Tobin corrupted by the Sith
Lord's influence. Canonically, he is persuaded to abandon the Sith after realizing Nihilus did not care about Onderon. Alternately, the Colonel can be killed in battle or, if he is not encountered at all, killed in the destruction of the Ravager.