| Zwordsman |
Don't think so. the underground chemist thing looks like it only deals it on target since it has to be directed at a creature and not a square (implying the splash does not sneak attack)
A fun note. Depending on what you want out of it. TOxicant should stack with trap breaker. If you wanted to start laying explosive mines around too. Loses poison resistance etc sadly. But Toxicants are already immune to their own poison. So it'd just be a problem with the rest.