You Were Asked to Open a Shelter, but You Were Not Asked to Guard the Surrounding Areas?

A boy from a bankrupt spiritual beast shelter + a beastmaster who was judged to be an F-level beast master, awakened the "All Things Shelter Platform" - four-in-one containment, entry, synthesis, and proficiency; on the surface, he takes in stray beasts, trains failed students, and actually raises a bonded army to guard the four directions.