I don't know. Thinking about it now I must have misinterpreted what the monolith did. In my mind I interpreted it as functioning sort of like a clentaminator, where it just cleans up the crimson/corruption in the world.
Your username appears in the top right corner of the forums. Hover your mouse over that and a drop down box will appear. One of the options will say "avatar." Click on that and a menu will pop up with a few options for changing your profile picture.
The best way to do this is with all of the attack speed modifiers possible. The beetle armor set using the beetle scale mail (chestplate) largely increases attack speed. Other than that, there are accessories you can use, such as:
Feral claws (ASI 12%)
Power glove (ASI 12%)