Opelle held the rank of captain aboard the Valiant back in 3951 BBY. During the time when the Czerka Corporation seized control of Citadel Station as part of their attempt to dominate the Telosian Restoration Project, Meetra Surik made Opelle aware of what was happening. Opelle, who at the time was leading the investigation into the destruction that occurred at the Peragus Mining Facility, instead commanded that they dock at the station and deploy Republic troops.
In the video game Star Wars: Knights of the Old Republic II: The Sith Lords, Opelle was originally intended to be a character involved in a storyline centered around Czerka's forceful acquisition of Citadel Station, but this plotline was removed before the game's release. Consequently, neither Opelle nor the ship called the Valiant are present in the final released version of the game. Despite this, Opelle's recorded lines of dialogue can still be found within the game's data files. Furthermore, a droid located within the Telos Security Force headquarters mistakenly identifies Admiral Carth Onasi's vessel as the Valiant during a conversation. This is different from the subtitles and the rest of the game, which refer to it as the Sojourn).
Based on this mistake, it's possible that Opelle's initial role in the game's development was akin to those of Admirals Onasi and Cede.