These protectors have almost unlimited powers to control the time. Their only goal is to preserve their existence, so the universe can stay in peace. It is because of this that they have had faced both heroes and villains such as the Avengers and the Scarlet Witch. For some time, they recruited Immortus in order to destroy the Avengers because the Time Keepers feared the expansion of humanity all over the space could be dangerous.
Finally, the Time Keepers decided to destroy all the alternative realities so they could remain as the only time guardians. Then, the time traveler Kang asked Rick Jones (Captain Marvel) if he could aid him to save the other realities. Rick accepted and they both managed to defeat the Time Keepers. During the battle, they seemed to die, but it is unknown if they really are dead.
In Other Media
The Time-Keepers appear in the 2021 series Loki, which is part of the Marvel Cinematic Universe. However, they do not appear in person for the majority of the series, and instead are frequently spoken about and represented by a massive statue in the Time Variance Authority's headquarters. In the first episode, it is explained that eons ago, the Time-Keepers brought about the Sacred Timeline in the aftermath of a massive multiversal war. They created the Time Variance Authority to police the timeline and prevent variant branches from spinning off into alternate universes. However, in the penultimate episode, it is revealed that the Time-Keepers are actually androids created by the true creator of the TVA: He Who Remains.