Echelon is probably a Boss-class unit for the Industrial region. Him’s a steam-powered, cyborg Minotaur.
He’s the first to have the unique Heat mechanic: every action performed and every attack suffered increase a Heat metric. This metric is directly tied to Echelon’s damage output, growing as more Heat is generated. But, when the Heat exceeds its maximum value, he is disabled for a number of turns. Additionally, he has a skill that specifically reduces Heat, as well as some attacks that have Heat reduction as a side-effect.
It’s really similar to Sharla’s mechanic from Xenoblade Chronicles.