"Star Trek Into Darkness," released in 2013, was generally considered a hit. The film grossed over $467 million worldwide against a production budget of approximately $190 million, making it financially successful. It received mixed to positive reviews from critics, praised for its visual effects and performances, particularly Benedict Cumberbatch's portrayal of Khan. However, some fans criticized its plot and comparisons to previous films in the franchise. Overall, it performed well commercially and contributed to the continuation of the rebooted Star Trek series.

As of October 2023, Chris Pine's absence from "Star Trek 4" is attributed to contract disputes and negotiations that did not reach a satisfactory conclusion. Pine, who plays Captain James T. Kirk, and other cast members were reported to have disagreements over salary and terms for the film. The production faced several delays, and with Pine's potential exit, the future of the project became uncertain. However, discussions about reviving the franchise and bringing back the cast may continue.

In "Star Trek Into Darkness," the main villain is Khan Noonien Singh, portrayed by Benedict Cumberbatch. Khan is a genetically engineered superhuman who seeks revenge against Starfleet after being awakened from cryogenic sleep. His character is a reimagining of the original villain from the "Star Trek" franchise, specifically from the episode "Space Seed" and the film "Star Trek II: The Wrath of Khan." The film explores themes of loyalty, sacrifice, and the moral complexities of command in the face of immense threat.

As of my last update in October 2023, Chris Hemsworth's involvement in "Star Trek 4" has not been officially confirmed. Hemsworth previously appeared as George Kirk, the father of James T. Kirk, in the 2009 "Star Trek" film and briefly in "Star Trek Into Darkness." There have been discussions about the plot potentially involving time travel, which could allow for his return, but nothing definitive has been announced regarding his participation in the upcoming film.