In the first film, The Terminator (1984), Kyle Reese is a soldier from the future who is sent back in time to protect Sarah Connor from a Terminator, a cyborg assassin sent by Skynet, a self-aware artificial intelligence system, to kill her before she gives birth to John. Kyle successfully protects Sarah and helps her escape from the Terminator, but he is killed in the process.
In the second film, Terminator 2: Judgment Day (1991), Kyle Reese is seen in a dream sequence by Sarah Connor, who is now living with John in Mexico. In the dream, Kyle tells Sarah that he is John's father and that she must protect him at all costs.
In the third film, Terminator 3: Rise of the Machines (2003), Kyle Reese is not mentioned or seen, but his sacrifice is referenced by Sarah Connor.
In the fourth film, Terminator Salvation (2009), Kyle Reese is mentioned by John Connor, who is now a grown man leading the human resistance against the machines. John says that he considers Kyle to be a father figure, even though he never met him in person.
In the fifth film, Terminator Genisys (2015), Kyle Reese is a young man who is sent back in time to 1984 to protect Sarah Connor from a Terminator. However, this version of Kyle Reese is different from the one in the original film, as he is actually a cyborg himself, created by Skynet to infiltrate the human resistance. Kyle Reese eventually turns against Skynet and helps Sarah Connor and John Connor defeat the machines.
In the sixth film, Terminator: Dark Fate (2019), Kyle Reese is not mentioned or seen, but his sacrifice is referenced by Sarah Connor.
Overall, Kyle Reese is an important character in the Terminator franchise because of his role in protecting Sarah Connor and ensuring the future of humanity. His sacrifice and his relationship with Sarah Connor are central to the franchise's story and themes.