Remember, Rantzien is not an Native English person, so as he said, metaphors etc aren't going to be the case here. Every line is literal, but only one word in particular is metaphorical.
I know it's most likely wrong, but Alexander?
Putting my breath to rest - Alexander is destroyed by the Invincible.
anticipating twilight's end - I feel that twilight is the metaphor here, and it may relate to glory and hope. When Alexander appeared, it was to defeat bahamut.
in hope of finding love - unsure of this line, Garnet and Eiko were the ones who summoned him, therefore Garnet could have wanted to keep love and peace in the kingdom.
fighting sickness - sickness can mean to destroy ones healthy condition. The invincible took away that from Alexander.
Void was my brawl; - He was destroyed while fighting to protect the kingdom
it drenched me. - Removed his powers
