If your looking for a legendary Pokemon then Darkrai.
Otherwise,I suggest Umbreon,scrafty,hydreigon, or zoroark
.
Darkrai.
Ghost or dark pokemon
any Pokemon that is a dark type any Pokemon that is a dark type
Morty has ghost-type Pokemon, it's best to use a Pokemon that know's a dark type attack. Ghost Pokemon do not have many weaknesses but dark is strongest against them.
ghost or dark types
=====================DARKRAI===========
dark pulse faint attack crunch these are some of the best
Dark type pokemon didn't appear until Johto
Yes. Sableye is a dark and ghost type pokemon.
Ghost-type Pokemon are weak against Ghost and Dark-type moves.
You need a grass type, a fire type, a water type, an ice type, your legendary and a ghost or dark pokemon.
Dark-type pokemon are resistant to Dark and Ghost moves, and are unaffected by Psychic.