Once you arrive back at Castle Oblivion after finishing World Card Set 1, you'll bump into a member of the Organization - Larxene. After the cutscene, it'll be time for a boss battle.
Larxene is the second Organization member you face off against (the first being Axel in the first World Card Set) and won't take it lightly on you. Her main attacks are the use of her knives and thunder. She also heals herself occasionally with Item Cards. The best time to attack is when she's reloading her deck. Try to keep away from her Thunder attacks by either dodge rolling behind her or card breaking them, as these moves do a lot of continuous damage to Sora. Her throwing knives are best avoided as well, and can act as a nuisance when you're in the middle of a Sleight. Try to use Raid Sleights to your advantage here, and use as many Summon Cards as you can. Her attacks are:
- Larxene uses the knives she's holding as throwing knives. When she throws them at Sora, they grow larger and pack a powerful punch against his HP. It would be best to dodge this move.
- Larxene sometimes casts Thundaga, which acts the same as when Sora uses it.
- A move you'd be best card breaking, Larxene uses a thunder bolt to lift Sora up from the ground and stun him. He gets hurt for the moment he's stunned, and keeps losing HP until Larxene drops him back to the ground.
After you defeat Larxene, you'll get the Thunder Card and be able to move on to the next set of worlds.