According to our current understanding of physics, time travel into the past is not known to be possible. While theories like general relativity allow for certain scenarios where time dilation can occur, enabling someone to experience time passing more slowly or quickly relative to others, they do not permit backward time travel in a way that would allow one to change or interact with the past.
As for time travel into the future, it is theoretically possible under certain conditions. According to the theory of relativity, time dilation can occur when an object moves at speeds close to the speed of light or in the presence of strong gravitational fields. However, this would be relative to an external observer, and the person or object experiencing the time dilation would still perceive time passing normally for themselves.
Regarding crossing the universe, the universe is vast, and we have yet to explore its entirety. Currently, the speed of light is considered an absolute speed limit, meaning that it is not possible for anything with mass to travel faster than light. Therefore, it would be extremely challenging, if not impossible, for any physical being, including a hypothetical devil, to cross the entire universe due to the vast distances involved.
It's important to note that discussions about devils or supernatural entities generally fall outside the realm of scientific understanding and are often based on religious or cultural beliefs, mythology, or fictional narratives. These concepts are subjective and vary across different belief systems and stories.