Mission 09: Collect hearts
Team up with Marluxia, eliminate Heartless in Twilight Town, and collect hearts.
Mission 9 begins in an enclosed block of Twilight Town's Tram Common. Roxas must again collect hearts by defeating Heartless in order to fill the Mission Gauge. This mission has a whopping seven treasure chests, all of which are located around the Tram Common. Since there are so many chests, you will not be able to carry all of them and items dropped by enemies. Take the treasure chests' items over those dropped by enemies.
Navigate your way to the hole that leads into the woods. Past the woods is another area with a large group of Dire Plants. Take them out with Fire spells, or use Block to deflect their seed attack right at them, destroying them instantly. After defeating them all, you will have completed the mission.
In order to completely fill the Mission Gauge, you must defeat an incredibly powerful and dangerous enemy. When returning to the Tram Common, a Zip Slasher will appear in the north enclosed area of Twilight Town. It will attack you with a powerful stab and spinning attack that can Damage Drain you, then be still for a few moments. The key to defeating it is to have patience, dodge quickly when it becomes active again, and only attack while the Zip Slasher is still.
Defeating all of the Shadows in the Tram Common and The Woods is essential for getting all three Challenge Sigils. When fighting the Dire Plants, be sure to pick up all of the Munny before it disappears. Upon returning, there will be one new Shadow in the Tram Common that will fulfill the requirements for the third Challenge Sigil. Defeating the Zip Slasher is not required, but is necessary if any Munny disappeared/was not picked up. Equipping Treasure Magnet, especially if leveled up, will be a great help to this mission.