The phrase "most blood and thunder" is often used to describe something that is dramatic, intense, or full of excitement. However, there are several antonyms that can be used to describe something that is calm, peaceful, or relaxed. Some of these antonyms include quiet, calm, tranquil, serene, peaceful, easy-going, and laid-back. Using these words can help to tone down the intensity of a discussion or situation, bringing a sense of balance and harmony. Additionally, these words can be used to describe a particular environment or setting, creating a soothing and calming atmosphere for all who are in it.