Mission 74: Search for the impostor
Search for the Impostor.
Roxas and Axel must look for the Organization impostor who was sighted near Castle Oblivion. However, Roxas faints when they enter the castle and Axel takes him to Twilight Town. It is there where they meet the impostor.
Follow the impostor into the underground. Striking the impostor causes him to vanish from one location and reappear elsewhere. Look for the orange-red colored dot to appear on the in-game map to determine his next location. He doesn't attack back, so there's nothing to fear. When he finally appears by the south blue gate, he moves to the Tunnel.
Enter the Tunnel and chase the impostor from the southeast corner into the main room and back again. When the impostor slips through the south gate and out of Twilight Town, it's time to call it a day and RTC.
While the impostor can be tracked on the map, he will block many of your attacks, wasting your time. In order to get past his defense and damage him, bring multiple casts of Aeroga.
Also, equip abilities to boost your mobility, such as Haste, Glide, and Air Dash, leveled up if possible. Since you can't recover your health normally, equip Auto-Life to regain your HP if it runs out. Also note that the Second Chance ability will keep you from dying because of the HP drain. However, it won't protect you from Heartless attacks. If necessary, Limit Breaks would also be a huge help and can be useful, just remember to keep an eye on your surroundings. As time is tight on this mission, make sure to move as quickly as possible including be ready to quickly move onto the next part, though it might take a couple of tries to get all 3 Challenge Sigils.