Deaths of Organization XIII

This is just a discussion and overview of how each member was defeated and killed. These all come after a battle, so give your opinion on the battle (too easy, way to difficult, etc.) and if you thought they were destroyed in an interesting manner. The "defeated by" will only list characters the player controls, unless there is no player character that deals the final blow (ex. Vexen killed by Axel)

I. Xemnas - After seperating Sora and Riku from the others in a desperate attempt to destroy them and gain the power of Kingdom Hearrts, they engage in several intense battles, eventually culminating in Sora and Riku managing to destroy the leader of Organization XIII. He fades after being dealt a killing blow by the Keyblade Wielders.
Defeated by - Sora and Riku

II. Xigbar - He confronts Sora on his trek up The Castle that Never Was. After taunting Sora by calling him Roxas and telling him he is "Half the heroes the others were" (alluding to Terra, Ven, and Aqua), they begin a long battle. Sora ends up the victor.
Defeated by- Sora

III. Xaldin - After stealing the Beast's Rose and kidnapping Bell, Xaldin attempts to continue his plans to gain control of the heartless and nobody of the beast. Bell manages to steal the rose back and escape, causing Xaldin to be in a direct confrontation with Sora. After a difficult battle on the Castle Bride, Xaldin is defeated.
Defeated by - Sora

IV. Vexen - Vexen leads Sora to a card-world version of Twilight Town, hoping to help Sora realize the existence of Roxas and Nobodies. Marluxia orders his assassination to prevent this knowledge from getting to Sora. After being defeated by Sora in battle, Axel appears and incinerates Vexen, making him the first Organization member to fall.
Defeated by - Axel

V. Lexeaus - The Silent Hero confronts Riku in the basement levels of Castle Oblivion. In an attempt to gain control of Riku to counter Marluxia's control of Sora, Lexeaus attacks him. Although Riku wins the battle, he is knocked out by a strong blow from Lexeaus. However, Xehanort's Heartless possesses Riku's body as Lexeaus lets his guard down, dealing a quick final blow to the weakened warrior.
Defeated by - Riku (Xehanort's Heartless)

VI. Zexion - Zexion sends Riku to a card-world version of the Destiny Islands, in an attempt to break his spirit and ultimately eliminate him (after the death of Marluxia, Zexion has no more use for Riku, and clearly views him as to much of a threat). However, Namine gives Riku the strength to stand and fight, leading to a hard fought battle in the card-world. Riku wins, and severely wounds Zexion. Wounded, Zexion escapes and is found by Axel and the Riku Replica. After some goading from Axel, the Replica absorbs Zexion's life force (because he can apparently do that) in an attempt to become stronger than Riku.
Defeated by- Riku Replica

VII. Saix - The second in command of Organization XIII is fittingly the last member to fall before Xemnas himself. He confronts Sora in his own chamber, borrowing the power of the Kingdom Hearts Moon, sending him into a berserker state. Even with that power, Sora still defeats him, and he fades lamenting never regaining his lost heart.
Defeated by - Sora

VIII. Axel - After giving up on turning Sora into a heartless, Axel aids Sora in battle in Betwixt and Between. Realizing that they are outnumbered, Axel uses a full power kamikaze attack, killing the nobodies, but using all of his strength in the process. Axel makes peace with Sora as he fades away.
Defeated by- Suicide

IX. Demyx - Demyx confronts Sora during the Battle for Hollow Bastion. After dropping his aloof and carefree demeanor, revealing his emotionless nobody side, Demyx engages Sora in a difficult battle. Sora manages to defeat him, and Demyx fades away becoming the first organization member to fall in Kingdom Hearts 2
Defeated by - Sora

X. Luxord - Despite confronting Sora in Port Royal, Luxord merely manipulates the events and vanishes, not battling Sora himself. Their battle finally comes in his chambers in the Castle that Never Was, where he seperates Sora from his companions for a one on one time based battle. Sora manages to defeat him, slicing through a shield of cards to deal the final blow to the Gambler of Fate.
Defeated by- Sora

XI. Marluxia - Marluxia, in following with his plan to overthrow Xemnas, manipulates most of Sora's actions throughout Castle Oblivion. After the Riku Replica seperates Marluxia from Namine, Sora battles first a copy of him, then Marluxia's full power in the room behind. Despite having multiple powerful forms, Marluxia is no match for the keyblade master, and he fades away as well, his plan finally stopped.
Defeated by- Sora

XII. Larxene - A co-conspirator in Marluxia's plot, Larxene confronts Sora directly more often than Marluxia himself. After revealing that everything Namine has done was to harm Sora under their orders, she brutally beats him. However, he is saved at the last minute by Donald and Goofy, and a second round commences. Larxene is unable to overcome Sora's full power and fades away.
Defeated by- Sora

XIII. Roxas - Roxas spends his final days in a virtual recreation of Twilight Town, with fake memories and fake friends. However, Axel attempts to reclaim his best friend, leading to a series of conflicts in which Roxas regains his memories, and must decide wether or not to reunite with Sora. After defeating Axel in the Mansion of Twilight Town, Roxas angrily confronts Diz, however upon seeing Sora, he is pacified, and quietly rejoins with his original self.
Defeated by- Suicide (His status as "dead" is debatable, as he lives on inside Sora, however Suicide will be listed because he made the choice to end his own seperate existence)

XIV. Xion - Xion, being a Replica of Sora as opposed to a true nobody, decides she must return to Sora. However she is stopped by Axel, who takes her back to the castle but passes out form exhaustion. She is taken by Xemnas, who sends her to battle and absorb Roxas, as was the original plan. Roxas defeats her however, and so gains her keyblade and his signature Dual Wielding style. Her body slowly becomes Ice as she says a tearful goodbye to Roxas, pleading with him to save the hearts they captured from being used in Xemnas' plan.
Defeated by- Roxas

Personally, I thought the battle's against Luxord and Saix were overshadowed by the much harder battle against Xigbar only moments before them. Demyx's battle was suprisingly difficult since the other members of the Organization claim Demyx cannot fight, yet his boss battle is harder than many others. I thought most of the Organization deaths were fine, although I was kind of tired of Sora having to kill them all himself. Checking the stats we have:
Sora: 8 members
Riku: 1-2 (if you count Xehanort's heartless as Riku)
Riku Replica: 1
Axel: 2 (if you count his suicide as defeating himself)
Roxas: 2 (if you count his suicide as defeating himself)

 

Really? I found the Riku battles to be the easiest in COM. The predetermined deck takes sleights into consideration during your dark mode, making it incredibly easy once you transform.

Xaldin was hard for me the very first time, and then after that, he was cake.

 

Hardest as in Proud mode (US) or critical mode (FM+)?