Krelios said:
Lawful? Sure. Good, certainly not. If he only purposely infects his enemies and takes reasonable precautions to protect his friends, Lawful Neutral would certainly apply.
I've read this entire thread and seen precious few direct responses to this central issue.
Biowarfare, real life or not, is a very touchy issue. Some point out that it makes little difference to the dead how they are killed, aside from how much they suffer. Some point out that in many cases it is suggested that using poison and disease is an evil act. The exact details of why that is implied are really beyond the scope of this discussion.
Lawful neutrals care about the law. They do not care about mercy, unless their concept of the law includes it (which is rare, as mercy implies altering the harsh and unswerving dictates of the law.) They do not, unless they are leaning to good, care about the suffering of people who are their enemies anyhow. Nor do they care that they are doing evil, as long as it is in accord with the law. A lawful neutral person is plausibly entitled to slaughter villages as long as it is in perfect accord with the law he or she follows. Granted, that's a stretch, and it would have to be some pre-existing rule in order to not be a complete cop-out in a game, but it's true. LNs will do good or evil so long as it upholds their concept of the law. Good is easier to work with and causes less of a mess, so they might favor it for operational reasons, but pure LN isn't concerned with good/evil morality, only the pursuit of law.
No one doubts that the monk only intends to infect enemies. That's fine. The only issue here is
whether or not he is taking all reasonable precautions to protect his allies.
So this boils down to: what's reasonable? I think this thread pretty clearly shows that everyone has different ideas about that. Some people believe that a powerful weapon makes it worth the risks of accidentally contaminating teammates; some people don't believe that, and they argue that even using the thing constitutes an unreasonable risk to his allies.
Note that the fact that the character is LN and personally unconcerned with good and evil doesn't change the fact that paladins will still want to see him executed for not caring about the deaths of countless innocent children who caught the plague and died in the weeks after his passing. It's still an evil act, and the DM is within his or her rights to send angry paladins after the character.