High poly blade sculpted axe with Notches in it baked to low poly model with that has no notches in its mesh Is it possible to bake a notch of a high poly sculpt to a low poly mesh without having to add extra geometry to the low poly model. Would it be possible to use some sort of transparency map to make it appear that the lowpoly model has a notch on the edge of the axe blade? Modelling an axe for dota 2 if I didn't have to add extra geomtrey for notches in the axe blade I could spend the limited amount of tris on other parts of the axe.
No it isn't possible.

Baking a normal map only affects the shading of an object's surface to give the appearance of detail that would normally be created with extra geometry. A normal map cannot alter the outline of a mesh. You will need to have the notches in the outline of your low poly object.

While a displacement map can be used to move existing geometry, I don't expect it to fit into your usage. It would also mean having the geometry to displace.

Creating a transparency map would not get the result you are after. The material transparency can be restricted to certain areas but that area would be transparent from every angle, leaving the axe with a hole through it when looking towards the blade.