|This article is about the boss. You may be looking for the replica.|
Sora may fight Riku on Destiny Islands before reporting to Kairi for the first time. Riku is the most difficult challenge on the island. Riku's attacks are similar to other battles with his normal strikes. He has two special attacks. After four hits, Sora knocks Riku down, then Riku will jump back up kicking Sora if the player does not have him jump out of the way.
His other comes if Sora hits him while he is guarding three times; he will unleash a powerful strike, though this can be countered or dodged. The difficulty of this battle comes from falling off the small battle arena (if the player goes out of bounds, the player will lose). Riku is worth 5 EXP and gives a Potion on defeat.
Riku (Dark Mode)
Here, you will be reunited with Donald and Goofy (after playing with only one party member, the Beast, for quite a while). The Beast will not join you in this party, so make sure your Strength and Defense are up. Now, he is in Dark Mode, and has the Soul Eater with him. Riku can’t be hurt by magic, so use Dodge Roll to avoid lunging attacks, then counterattack him from behind.
His moveset is about the same as the battle in Destiny Islands, except much quicker and more aggressive, so Dodge Roll out of harm's way. Melee attacks are recommended for this battle - and like all other boss battles, heal when necessary. Good evasion, good timing, lots of physical attacks - these are sure to get Riku down rather quickly. If your stats are rather low, however, this can be a tiresome fight.
You may consider summoning Tinker Bell to restore your HP periodically.
Here, Riku is now possessed by Ansem, Seeker of Darkness, and wielding the dark Keyblade of People's Hearts. Before approaching him, re-stock Sora's items and make sure that he is in top notch condition. You are alone in this boss battle. It is strongly recommended that you equip Guard, Dodge Roll, Glide, and Counterattack. Also, it is highly recommended that you beat the 3 cups at Olympus Coliseum and get the Olympia Keyblade, and if you don't mind losing some MP, the Metal Chocobo can be useful as well. Riku's HP is made up of several bars.
In his first HP bar, he'll attempt to toy with you, passing around you and executing his standard two-hit combo; just simply dodge and attack him. Whatever combo that you use, try to refrain from executing the combo finisher (unless you equip Blitz ); Riku has fast recovery and can unleash devastating counterattacks. If you have equipped Ars Arcanum, save it for later. Also beware: magic only makes this boss counterattack with Dark Firaga.
After you drain his first life bar, Riku will start using a new attack; he'll spin around while swinging his Keyblade, similar to Sora's Vortex. He uses this attack very often, mostly to break your combos. During this time, try keeping yourself at a safe distance, but not too far, or Riku will make a high leap and attempt to stab you with his Keyblade, creating shockwaves that move sideways from his position. Now it will be a good time to use Ars Arcanum, but just use it a few times, and try saving your MP, because you'll be needing it later.
Eventually Riku will enter a powered-up mode, in which he invokes himself with darkness, and a purple aura surrounds him. During this period, his speed and agility increase, and he gains two new attacks; one involves throwing his Keyblade at you, similar to Strike Raid (be careful when countering this attack, as if it hits Riku he will use Dark Firaga).
Fortunately, his thrown Keyblade can be deflected either by guarding or striking with perfect timing; for each successful deflect, Riku will receive damage and be momentarily stunned. Seize this opportunity and bash him with all you've got. The second attack, he leaps into the air and stabs the ground, creating dark geysers that appear in random spots. It's usually after this attack that he powers back down, but he'll power up again shortly.
When Riku's health bar drops to his final one, he'll become more and more aggressive, and his powered-up mode becomes permanent. He'll use a new attack, Dark Aura. Riku's Dark Aura is a predictable move, but it can be difficult to dodge. When you see him floating and charging, keep your distance from him and High Jump right before he starts shooting around. Immediately execute Glide and move around in a circular fashion.
Near the end of his assault you'll have to repeat the phase and start Gliding again. This attack's finisher is a powered-up dark geyser attack that covers about 60% of the arena, so it'll be pretty hard to evade it. Alternatively, when he charges to one particular end of the arena (he usually starts with the top left corner), jump and stay there: Riku will not charge into the same area twice. Stay there until the finisher is executed (because he will not hit that area).
Attacking and counterattacking are good tactics while Riku is in this form, just pay attention to what he says and heal occasionally and you should be fine.
Note also that aside from the first hit, he cannot use Dark Aura when you stand RIGHT next to the computer. However, he will Strike Raid and combo you immediately afterward.
When Riku's health reaches critical levels, be sure to finish him as fast as you can, for he will pull Dark Aura very often, thus prolonging the fight. Aside from that, he'll start to keep his distance from you, so track him down and continue hacking at him and you'll eventually win. Suggested Keyblades to use are the Olympia and Metal Chocobo—but ultimately, no matter what Keyblade you use, fight Riku tactically and you will take him down.
A good pattern to get into that causes great damage is immediately after executing a full or half combo, spam Guard, and repeat, almost never giving him a chance to attack.
Kingdom Hearts II
Sora battles the hooded Riku in the form of Xehanort's Heartless in a one-on-one match in the Land of Dragons. While not a full-fledged battle, Riku attacks with slashing combos, dark magic, and the Dark Firaga attack. Both attacks can be dodged rather easily. Not only does he attack you, but he also attacks any Rapid Thruster on the battlefield that gets near him.
He remains silent and can be damaged with the Reaction Command provided by the Rapid Thrusters that surround him. If you bring many Ethers into the battle, a good way to damage Riku is by using Trinity Limit. The battle ends when Sora deals enough damage to Riku. You could just battle the Rapid Thrusters since they are endless and try to level up.
Riku will block almost all of Roxas's attacks, so the point is to simply attack with your Keyblade or area spells like Aeroga in order to herd him to the southern tunnels. While several Heartless will appear throughout the area, just ignore them and focus on Riku. Once Riku is chased into the southernmost tunnel, he will escape through a dark corridor and the mission will end.
In this battle, you will lose your Dual-Wield power, only left with the Oathkeeper in hand whilst Riku wields Oblivion. Riku is particularly tough to defeat due to his high HP count. His normal attack consists of a flurry of stabs, finishing it off with a mighty thrust that comes out rather quickly. This can be blocked fairly easily, however, and a counter attack can be used (if the Block-Counter panel is equipped). Riku possesses several special attacks which are signaled through body gestures. If he raises his arm up, he will cast Dark Shield, which briefly raises up a barrier in front of him. Attacking him while the shield is up will cause him to immediately counter it with a quick thrust. If he jumps back, he will cast Dark Firaga in which he shoots forth a blue energy blast.
Unlike the previous games, Dark Firaga will home in on you. It moves fairly slowly, however, and can be easily blocked. If it connects, he will immediately follow up with a downward slam similar to Impulse. At times, he'll perform Dark Break, in which he leaps into the air and teleports to your location and strikes the ground, releasing a blast of energy, which he repeats two more times. This can be avoided with Dodge Roll or more effectively by Gliding.
Once Riku's health starts to run low, he will gather up power and infuse his Keyblade with dark energy, increasing his range and power, similar to the sword Roxas wields in his Limit Break Event Horizon. Here he becomes much more aggressive in combat, becoming immune to flinching, and will begin to utilize Dark Aura, charging you with powered thrusts from all directions and ending it with a downward thrust that releases small bursts of energy around him; this attack is best avoided by Dodge Rolling. Usage of Cure, Cura, or Curaga and your Limit Break will prove most effective in this battle.