The Timekeeper is the main antagonist in the film, Spy Kids 4: All the Time in the World. Initially he was presented as a villain who seeks to stop time in the world because people has been wasting time and vows to take away time from the world. As the plot progresses his true motives were revealed.
Origin
Back in the 1930's the Timekeeper's scientist father brought him to a laboratory where his father and his co-
Danger trapped in time
workers were conducting a experiment on time travel called Project ARMAGEDDON. His father told him not play and wander in the lab but he did not listen and he was caught up in his father's experiment and froze in time. His father found a way to unfreeze him in time until he died due to old age.
One day, a group of scientist found a substance from a meteorite known as the Chrono Sapphire which has special qualities, including the ability to unfreeze the Timekeeper in time. When the Timekeeper was unfrozen, he realized that all people he knew and love already passed away.
Under the name Danger D'amo (most probably not his real name), he became the head of the OSS, A spy organization.
Name
The Timekeeper unmasked
The Timekeeper's name is Danger D'amo, an annagram. If you scramble the letters of his name, you can spell the word "Armageddon". His real name most probably can't be Danger D'amo and his birthname is never revealed.
Motives and Scheme
When the Timekeeper first appeared to the media as a villain he stated that his goal is cause Armageddon by stopping time. He believes that people does not value time but wastes it. In order to do this he must activate the Armageddon device.
Danger's older self
However the real purpose of the Armageddon device is not to stop time but for him go back in time. The Timekeeper longs to reunite with his father and to prevent his death. He already went back in time more than once but failed and created multiple versions of himself which served as his minions including Tick Tock. He finally suceeds, probably that the Chrono Sapphire went along with him through the time portal created by his Armageddon device. He reappered immediately where the portal once were but reappered as an older version of himself. Telling Cecil and Rebecca that they are right that he can't change the past and that his father still died. He told them that people should not live in the past but live a life moving forwards.