You can roll a d4 in place of the normal damage of your unarmed strike or monk weapon. This die changes as you gain monk levels, as shown in the Martial Arts column of the Monk table.
So a blowgun, despite not using a damage die and instead using a static value, should also technically scale since the ability in question specifies damage and not damage dice. Unless I'm totally mistaken, a kensei with a blowgun should be able to roll dice. Currently does not seem to be working that way.
RAW, Monk weapons do this:
So a blowgun, despite not using a damage die and instead using a static value, should also technically scale since the ability in question specifies damage and not damage dice. Unless I'm totally mistaken, a kensei with a blowgun should be able to roll dice. Currently does not seem to be working that way.