|Stationed:||USS Enterprise (NCC-1701-C)|
|Rank:||Lieutenant junior grade|
In an alternate timeline, during the battle with the Romulan warbirds over Narendra III, the Enterprise-C was pulled through a temporal rift to the year 2366. In this timeline, created by their absence from Narendra III, the Klingons and Federation were fighting an extended war. When Captain Garrett was killed in battle with the Klingons, Castillo took command of the vessel. Under his command, the Enterprise-C returned through the temporal rift, restoring the timeline. Castillo's fate is unknown, though it is presumed he was killed by the Romulans.
There have been two accounts of Castillo's fate. One in which he was killed by Romulan General Volskiar shortly after the crew's capture in order, and the other, in which he was repatriated and survived into the 2360s, briefly glimpsing the primary timeline's Tasha Yar at the commissioning of the Enterprise-D. (ST novel: Vulcan's Heart, TNG short story: "The Fourth Toast")
|Officers of the starships Enterprise|
|NCC-1701-C:||Garrett||Castillo | Fredericks|
|NX-01 | NX-01 | NCC-1701 | NCC-1701 (alt) | NCC-1701 | NCC-1701-A | NCC-1701-B | NCC-1701-C | NCC-1701-D | NCC-1701-E|