In this (extremely long) passage, I found the line "night found him leg weary" to be an example of personification. This technique makes non-animate objects do human actions. Night can't actually find someone, so it is personification. Another example of this might be "the stars danced in the sky" since they can't really dance.
The statement that best explains Brutus’s motivation in this scene is Brutus wants to atone for Caesar’s death, and thinks he can do so by killing himself.
Brutus wants to expiate his action of killing Caesar, he felt guilty for it because after Caesar’s death Rome got worse and by killing himself he could do it so.
