In Norse legend, the guardian of the Bifröst bridge, which connects Midgard (Earth) to Asgard (the realm of the gods), is the god Heimdall. Known for his keen senses and ability to hear grass growing, Heimdall stands watch, ready to sound the Gjallarhorn to alert the gods of any impending threats, especially during the events of Ragnarök. His role reflects themes of vigilance and protection in Norse mythology, emphasizing the significance of safeguarding the divine realms.