Scorpia is one of many NPC/Bosses that are located in the wilderness. To get to Scorpia talk to The Crazy Old Wizard who is located North-West of ::home, he can be found at the end of the North West Path in the Thugbob building. You also need to have 65 million coins in your pouch to teleport there.
For this NPC the armour recommended is Torva, Pernix or Virtus armour. If you got better armour you can wear it too. But BEWARE! because this NPC is in the wilderness. If you have a fast hitting weapon that is not on the ::oplist pray Soulsplit (92 Prayer required) as well as Turmoil (95 Prayer required). Be careful as Scorpia will poison you.
It is recommended you use an ak-47 as it is one of the only fast hitting weapons allowed in the wilderness.But beware of Pk'ers.