If I want to distinguish between a musician's songs that are overall slower, softer and/or more sentimental, what would I call these songs? I am specifically focusing on heavier music such as rock or even metal where the musicians would generally do more intense music but decide to either do an entire song completely like this, or even start this way and then pick up into their normal style halfway or towards the end. I have heard the terms "ballad" and "power ballad" but I'm not sure if these apply to heavier genres of music as well, since as far as I've heard at least, a rock/metal ballad sounds different to a pop or classical ballad.
Two examples which are close to what I mean, while still sounding within their respective genres.
Metal song Example:
Rock song Example: