This achievement is gained once Laddersmith Gilligan gives you a Melu Scimitar.
He is found after the second bonfire in Earthen Peak. Go up the stairs (an enemy will fall upon you), then out of the door to your right. Here, there is a open corridor with wooden barriers along it. Hit the first barrier as you enter and walk along the new path to the left, along the edge of the tower. Laddersmith Gilligan should be standing there. Talk to him and buy his ladder for 2000 souls, then exhaust his dialogue. This will move him to Majula.
Once he is at Majula he will sit next to the pit. Simply purchase the ladder worth 12000 souls, and then talk to him until he gives you the scimitar.
Note: An alternative way to get him to Majula is to simply defeat Mytha, the Baneful Queen, who is the area boss of Earthen Peak. (Thanks to Sliktor for pointing this out).