Duskull is uncommon, not rare but its better to catch it if you don't have one
It is very rare but you can catch it at mount Pyre.
They help you catch rare Pokemon such as duskull and riolu. For example: I caught my duskull using peak objects in the swamp area.
on the moon
you can find it on route 224 (with a pokerader) NOTE: this is very very rare so it could take you Weeks to find it.
Pokeradar on Route 224. It's easier just to catch Duskull in the Lost Tower at Night in Platinum. (Duskull don't appear there in D/P, only Platinum.)
You can catch Duskull in Pokemon Platinum by going to the Lost Tower that is near Solaceon Town however you can only find it at night.
Use PokeRadar on Route 224. There is a 2% chance and the Duskull will be level 23.
Turnback cave.
Use Your Pokéradar (obtained with national dex) in route 224 Duskull is rare
you can catch it at the summit of mt. pyre the same way you catch chimecho. but it is also extremley rare just like chimecho. mostly you wiil find shuppet wich i absolutly hate because they always block me from catching mightyheyna
On route 224 with the pokéradar.
After you catch giritina youll come to spring field and it will be there in the grass!