What trainer has a monferno in platinum?

- if your starter pokémon was turtwig, then your rival will have one

- if your starter was piplup, then the prof. grandchild should have it. (dawn/lucas, whatever their names are)

- if you started with chimchar, then you just have to evolve it DUH;D

You can also see one in a double battle in route 212 (on the heart home side of it near the start of the marsh).

it's a doube batle against two Pokemon ranger's. It is level 31. They also had a leafeon (and a marille??)