sentinel (noun)

1. The fashion-forward sentinel stood at the entrance of the designer boutique, ensuring only VIP guests were granted access.

2. In the animated series, the sentinel guarded the secret treasure hidden deep within the enchanted forest.

3. According to Greek mythology, the sentinel was tasked with watching over the entrance to the Underworld to prevent any living souls from entering.

4. In the popular anime series, the sentinel protected the city from alien invaders using their extraordinary powers.