The mythical being known for its fierce loyalty and often featured in tales of heroism is the hound, specifically embodying characters like Fionn mac Cumhaill's faithful hound, Glen. Hounds represent loyalty, bravery, and fidelity in various cultures, acting as protectors and companions to heroes. This loyalty is frequently celebrated in legends, where the hound's dedication leads to their owner's triumphs and adventures. Such themes highlight the bond between humans and animals in folklore across traditions.