As one of the Basic Series Spell Techniques, the Magical Barrier is an essential for most magicians, even for Magical Girls.
The barrier serves many purposes. Firstly, it can act as a defense against others' Magic Power attacks; secondly, it can create an enclosed space for trapping enemies, protecting oneself, soundproofing and isolating noise, or even serving as an experimental site. It's incredibly versatile.
The colossal Magical Barrier that now enveloped the orphanage was also an application of this Spell Technique.
However, Tian Sheng was not capable of achieving such a feat. To have a Magical Barrier cover such a large complex of buildings was beyond the reach of even the most advanced controllers, let alone individuals. It had to be the work of an entire group.
It must have been the work of the group chasing after him.