"To live and die against all manner of folks?"

Solution 1:

It is one of the many uses of the word 'against'.

5b. Indicating a possible or anticipated danger: so as to be wary of or alert for.

Oxford English Dictionary

The OED does not list it as archaic but the references for the meaning (5b) finish in 1997 and the one reference I found most suitable to the above question was from 1650:

1650 Bp. J. Taylor Rule & Exercises Holy Living ii. §5 Men stand upon their guard against them [sc. inquisitions], as they secure their meat against harpies and cats, laying all their counsels and secrets out of their way