Lights Bane or Blood Butcher
Lights Bane: This Weapon can be achieved by geting demonite ore. How to get demonite ore is by slaying the Eye of cthulu or by Slaying the Eater of worlds. Then you have the right ingediants. Next forge your ore into bars. Then get a anvil and craft the lights bane. Blood Butcher: how to get the blood butcher is a lot similar like the lights bane but the lights bane, but it do's more damage. How to crimtane is facing the Eve of cthulu or the brain of cthulu. Then make it into bars and done!
The murmasa is a little harder to find requires a LOT of keys to find a murmasa. First go to the dungeon at night. Then talk to the old man. One of the options are Curse. Press curse. You will summon the skeletron. Beat skeletron. Then you have permission to go to the dungeon. Without faceing the dungeon gaurdian. Then you can gather golden keys. Unlock golden chest to find a murmasa.
Blade of Grass
How to get the blade of Grass is a lot of farming to do. To start off is to travel to the jungle. When you arrive, you want to go to the under ground. You at least want to get 15 hornets stingers and a LOT of jungle spors to craft the Blade of Grass.
The Fiery Greatsword is a lot stronger than the other swords. How to get this sword is to go down in the under world and get some hell stone witch is your main ingredant for this sword. While your still in the under world, grab a hell forge because the hell forge is how you craft hellstone bars. Then go to a anvil and craft the Fiery Greatsword.
Great, now you have collected all four swords to craft the nights edge. Now you want to go to the evil part of your world to craft this blade. Find a demon / crimson altar. Craft the nights edge and done.