If you use software, beware. Some might be detected as cheating software by some games. Though key remapping is usually not a problem, it is the same you can do with software shipped with your mouse or keyboard. If you have 5 mouse buttons, there is a need to make them usefull ;-)
A simple autofire would be this in ahk. ("Click" sends a left click). But you would lose the ability to do drag and drop and would accidentally do double clicks, if you put in on the left button itself. Better use an unused Mousebutton or a an unused key (just replace both "LButton" with "f" or "Space" or whatever). The winactive makes that one only work if the active window starts with the name Heroine (side effects include, that if the website you are browse starts the same, the remapping will occur there too)
#IfWinActive, Heroine
LButton::
While GetKeyState("LButton", "P")
{
Click
Sleep 200
}
return
#IfWinActive