Armaldo learns slash at lv. 55
For more Info about pokemon's check Serebii.net
Jonsi:D
Lv.24
he learns slash on level 42.
The move slash is learned at level 38.Hope this helps.
It learns slash at level 28 I think
Crobat learns air slash at level 51
Tranquill learns air slash at level 32
Level 31
it learns it when its caught
Sceptile, to my knowledge, is incapable of learning Night Slash.
At level 80 it learn Aqua Tail and at level 90 Aura Sphere.
It learns air slash at level 62 on the 4th generation games
Togekiss learns air slash at base level, so you have to use a heartscale in order to be able to teach Togekiss air slash.