Murray Serrintella was a very successful second-story man in the city of Crowns Pointe. So successful, in fact, that he was approached by the local crime boss, Willard "Mad-Dog" Duffo to join his organization. When Murray refused some of Duffo's men crippled Murray. Using is mechanical knowledge he constructed a spider-like body to give him back his mobility. As Arachnus, he killed Duffo and took control of his empire becoming the new crimelord of Crowns Pointe.
Arachnus has an arachnoid torso that he built. It provides him with immense strength, it can help him scale walls and it holds a vast array of weaponry. As the crimelord of Crowns Pointe he has the finances to make whatever modifications he needs to his suit.