# his ... him

The words "his" and "him" refer to Leviathan.

# terror dances in front of him

The abstract noun "terror" can be translated as the verb "be afraid." AT: "when people see him coming, they are very afraid" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])

# they cannot be moved

This can be translated in active form. AT: "no one can move them" (See: [[rc://en/ta/man/translate/figs-activepassive]])

# His heart is as hard as a stone

A rock or stone does not change and become soft. Possible meanings are 1) Leviathan's physical chest and the organs inside it are physically hard or 2) Leviathan is not afraid of anything or 3) Leviathan is spoken of as a person who kills without ever being sorry. (See: [[rc://en/ta/man/translate/figs-simile]] and [[rc://en/ta/man/translate/figs-personification]])

# a lower millstone

"the hardest of rocks." The lower millstone is the larger and harder of the two rocks used to grind grain. It would be the hardest rock people could find.