Sources say... Night Slash...
he learns slash on level 42.
Greninja does not learn Ice Beam by leveling up. You will need to teach it TM13 containing Ice Beam.
Kabutops learns attacks such as Scratch, Harden, Absorb, Leer, Mudshot, Sand Attack, Endure, Aqua Jet, Mega Drain, Slash, Metal Sound, Ancientpower, Wring Out, Night Slash and Feint.
it learns it when its caught
I think night slash because more Pokemon can learn slash but few can learn night slash if it weren't a TM
Sceptile, to my knowledge, is incapable of learning Night Slash.
Absol learns the move Night Slash at level 41. Absol also learns the Psychic type version of Night Slash called Psycho Cut at level 47.
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See related links section.
Gallade can learn night slash, but not by level up. To teach Gallade night slash the player most go to Pastoria city and go to the south part of the city then go into the house at the top right of the southern part of the city. There is a guy who can teach Gallade night slash for a heart scale and all other moves it learns before that. I hope that helped!
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Sources say... Night Slash...
First, do not evolve your sneasel, second, find a heart scale, third go to the move relearner's house. Give him the heart scale and select your sneasel to relearn night slash
there is no night slash in diamond
If you breed it with a Ditto or another Weavile, (of the opposite gender) it should start to learn moves.
Sorry But Treeko Starts Of With Night Slash So At Level One But You Can Go Fishing Near Evergrande City And Catch Some Luvdisk With A Heart Scale Attached To It Then Go To Lavaridge City And Give A Guy a Heart Scale And Then He Can Reteach Sceptile Night Slash.