Arceus, but it depends what....
Type
Level
Opponent
On the top of Mt. Cornet
Nobody has answered your question because it is grammatically incorrect. What do you MEAN, down? And why do you WANT to get rid of TMs?!
trade from platnem
you have to put a shiny carizard and shiny ditto if that dosent work put shiny charzard and ditto in the daycare.
same as diamond and pearl. in snowpoint city
you beat all the other gyms then after you catch giratina (or beat it) Cynthia will tell ya to go see prof rowan. he'll talk to you and say that the blackouts over and then you go to sunyshore city.
You have to evolve it from duskull. Then you evolve it into dusknoir using a reaper cloth. You have to trade it while duskclops is holding it. You can find a reapercloth in a house at Iron island once you obtain the National Pokedex. To get to Iron island you go to canlave city and talk to the sailor on the other side of the dock. Ofcourse you have to have Pokemon Pearl, Diamond, or Platnem.
There is no best Pokemon on Pokemon HeartGold.
the best Pokemon you can catch in Pokemon pearl is heatran
the best pokemon to use is mudkip.
the best Pokemon are mewto and the rarest Pokemon ever mew.
the best Pokemon for the Pokemon league is definetly latios