As on today the fastest weapon would be darts but there not very strong but still very fast, a better option would be an abyssal whip as its strong and fairly fast.
Darts and throwing knives are the fastest range weopons. Scimitars are the fastest malee.
Godswords.
advice: get a weapon
A Weapon
There is no weapon stash in Runescape. If you need a sword or armor, you can either buy it at the Grand Exchange located at Varrok, or you can make your own.
There's weapon stores in almost every town around Runescape, look for a Sword, Bow, or battleaxe icon on your mini-map.
nothing
If you have a weapon in your inventory, click on it to wield it. This will un-wield any other weapon you have in your weapon slot.
Any weapon that has a great crush bonus:BattleaxesMacesMaulsWarhammers
all you need to do to get poison off of a weapon is use a cleaning cloth.
Dragon claws
Gravite shortbow.