Mission 07: Collect hearts
Team up with Axel, eliminate Heartless in Twilight Town, and collect hearts.
Axel is paired with Roxas for his first real mission. After the mission, they observe three kids celebrating summer vacation, noting their strange behavior compared to Nobodies. Axel tries to explain to Roxas that their behavior, particularly laughter, is because they have hearts.
To complete this mission, you must defeat Emblem Heartless to collect hearts. Take this opportunity to practice accumulating Heart Points. Your main focus should be on destroying Emblem Heartless and maintaining a chain. Defeating Shadows and Possessors won't net you any Heart Points, but will help extend your chain. Attack the Pureblood Heartless to start your chains, and to keep them going when Emblem Heartless become scarce.
Head down the Side Street from your starting point, in the direction of Station Heights. There are three Shadows here; defeat them to begin a chain. Upon entering Station Heights, head up the slope. You will be ambushed by Yellow Operas and Possessors. If possible, defeat the Possessors first to extend your chain. Once you defeat all the enemies, continue to Station Plaza. Here you face more Yellow Operas and a couple Scarlet Tangos. Be careful not to target the Scarlet Tangos with Fire magic, as it will heal them. After defeating this group of Heartless, you will clear the mission goal.
Return to Station Heights. If you plan to fill the Mission Gauge completely, be sure to defeat all the Heartless on the way. Two Yellow Operas and a Dire Plant appear on your way towards the Side Street. Past the entrance to the Side Street is another Dire Plant. Back on the Side Street are two more Yellow Operas and a Shadow. The Yellow Operas are the last Emblem Heartless you need to defeat to fill the Mission Gauge.
Once the Mission Gauge is full, you can return to the bottom of Station Heights to face one extra Heartless: a Bulky Vendor. These Heartless not only are harmless, but they also drop incredibly rare items—if you defeat them! If these Heartless are not quickly eliminated, they flee the area. To dispatch of the Bulky Vendor quickly, cast multiple Fire spells.
It is best to revisit this Challenge Mission once you have acquired Blizzard magic. This is the weakness of the Scarlet Tangos, and can take out more than one in a single cast. Cast Blizzard on the Scarlet Tangos, and earning three Challenge Sigils should be smooth sailing.