The commander of the Romulan warbird Terix, who shadows the Enterprise-D in 2370 as both ships search an asteroid field for the wreck of the USS Pegasus.
Commander Sirol appears in the seventh-season episode The Pegasus. Romulan intelligence has learned that the lost ship may be recoverable, and the Terix reaches the Devolin system first. When the Enterprise arrives, Sirol and Picard hold a meticulously polite conversation in which each claims to be doing innocent survey work and neither believes the other.
Once the Enterprise has entered a large asteroid to reach the wreck, Sirol seals the opening behind it, then offers with every courtesy to carry its crew to Romulus.
The ship escapes by using the illegal phasing cloak salvaged from the Pegasus to pass through solid rock. Picard then decloaks in full view of the Terix and tells Sirol that his government will be hearing from the Federation about a breach of the Treaty of Algeron. Sirol was played by Michael Mack.