The tricky thing here is that when you modify a verb, you are saying something about how that verb takes place, and that necessarily involves the rest of the clause, including the subject. In this case, we're saying that this battle ranks as the bloodiest. In what way? There were all those casualties. In a sense, it doesn't matter which word we tie the modifier to, and in some cases there can be more than one right answer to that question. Here, however, we are saying how the battle ranks as the bloodiest, so we could say the modifier applies to the verb or to the whole clause. We wouldn't say it just applies to the adjective (bloodiest). That would imply that we're only changing the extent of that one word, as the word "very" does to "talented" in the sentence "She is a very talented journalist."
As for initial modifiers, they often
seem to modify the subject, as we see here:
Wishing to remain anonymous, the newspaper did not print the donor's name. [Incorrect]
Wishing to remain anonymous, the donor requested that the newspaper not print her name. [Correct]
Many people would explain the error in the first version by saying that the modifier should apply to the *donor* and not the *newspaper.* However, this is not quite right. "Wishing to remain anonymous" is an adverbial modifier, and it modifies an action. Since in the first sentence, the only action is on the part of the newspaper, there is nothing correct for the modifier to apply to. In the second case, the modifier is able to apply to "requested." The idea here is that she made this request
because she wished to remain anonymous.
The confusion comes because even if we have two actions, we still want the modifier to go with the first one. Basically, we see "Wishing to remain anonymous" and want to know right away *who* is wishing. So this sentence is still incorrect:
Wishing to remain anonymous, the newspaper agreed not to publish her name when she called the office.
You'd think that we could apply the initial modifier to "she called," since adverbial modifiers don't follow the touch rule. However, this construction is needlessly confusing. So the short version is that we can treat an initial adverbial modifier as if it were a noun modifier, because the first noun we see should be the one performing the modified action.
I hope that all made sense. Let me know if I can clarify.