In "Demon Slayer," the Thunder Breathing technique is a powerful form of swordsmanship that focuses on agility and speed, utilizing lightning-like movements to strike down demons. This technique is significant as it is one of the five elemental Breathing Styles that Demon Slayers use to enhance their combat abilities, making them more effective in battling against powerful demons. Thunder Breathing is known for its incredible speed and precision, allowing its users to deliver swift and deadly attacks, making it a crucial skill for Demon Slayers in their fight against evil.