WARNING: This page is about a different car, the 2003 Mitsubishi Outlander. However, it is still accessible from the selected car via links, so may be relevant.
Set special tool MD998778 as shown in the illustration.
Fig 1: Setting Special Tool
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Screw in the center bolt of the special tool to remove the crankshaft sprocket.