Starting with Saryn Prime, prime warframes often come with a cinematic trailer, narrated by Executor Ballas. His narration reveals tidbits of information about the nature of the warframes, and so they are contained here.
Prime warframes often release simultaneously with their Prime trailers, but there have been many exceptions, where the Prime trailer was delayed due to constraints on the animation team or other factors. The Hydroid Prime trailer in particular is notable for being released roughly three years after it would have normally come out.
After Mirage Prime, there was a long gap from 2017 – 2021 where no Prime warframes received Prime trailers, though some of these were accompanied by Leverian exhibits. Prime trailers resumed with Octavia Prime, but occasionally a Prime warframe will not receive a trailer (Garuda Prime and Baruuk Prime). In 2023, for the first time, a Prime trailer was released significantly before the Prime warframe was made available in-game (Grendel Prime).
Discussed in: Prime Warframe Cinematic Trailers