Having collected all 20 Dark Magic and "beaten" the Pirate Master, it's time for the True Battle for the Good End!
-Note 0: Obviously, you should have maxed out all upgrades and items.
-Note 1: Once again, Super Monster Milk, Super Pike Ball, and Bubble Shield
-Note 2: As you lose ALL the Pirate Weapons, you can NOT double-jump or hover for safety! Also no ranged attack.
True Battle Part 1 - 1000 HP
-1: Cannon Ball Phase - He fires 3 cannon balls which bounce quickly across the stage then they pass back the other way. (DO NOT LET THEM TOUCH YOU.) The best way to dodge them is to start at the far right corner (chance for some damage!) then after the first lands right in front of you run forward ALL the way to the far left corner, then repeat when they come back.
-2: Sword Rain Phase - Swords prepare to fall across the whole stage. Stand in the only open space! If you don't see an open space, it's on the far end of the area, run! (DO NOT TOUCH THE SWORDS YOU AS THEY FALL OR WHILE ON THE GROUND)
-3: Pistol Barrage Phase - Four pistols fire a barrage of bullets. Bubble Shield for the win! (DO NOT TOUCH THE PISTOLS THEMSELVES)
-4: Shadows & Platforms Phase - Three moving platforms appear, each with a shadow copy of the Pirate Master appearing to do magic attacks (Bubble Shield works!). Get rid of the shadows (They only have 1 HP) then attack the Pirate Master's head! (His head DOES NOT hurt you, so tear into him!)
-5: After a bit he returns to step 1, repeat until you clear Part 1! (If you do it well, you can clear it in only two rounds)
After you have absorbed your Light Magic, it's time for Part 2!
True Battle Part 2 - 1000 HP
-Note 1: Despite her "upgrade" to Hair Whip doing "999 damage", it's actually still just regular, so make sure to use your Super Monster Milk and Super Pike Balls for max damage!
-Note 2: This fight is basically the same as Part 1, but with a bit more added.
-1: Cannon Ball Phase - He fires 4 cannon balls, the fourth one will try to track your dodging. (This is likely your only real risk of damage.) Same strategy as before, go to the far right corner and wait (maybe get a couple free hits in) then run non-stop to the far left corner as soon as the first one lands right in front of you, then repeat from the other side.
-2: Sword Rain Phase - He first shuffles the swords before dropping them, to make it a bit harder to be in the safe spot. Just be ready to react quickly!
-3: Pistol Barrage Phase - After firing, he will throw the pistols themselves at you. Crouch in a corner to guarantee dodging them! (Keep up that Bubble Shield!)
-4: Shadows & Platforms Phase - Literally the same as before. 3 Platforms with a Shadow on each. (And keep up your Bubble Shield!)
-4.5: Repeat steps 1-4 until enough damage is dealt... then... Cut scene to Risky's plan!
-5: Final Round: You have to simultaneously keep his head in place by Hair Whipping it (Pike Balls won't help) while firing the shots from the cannon commandeered by Risky (They take a moment to travel, so you have to keep him in place before and after firing!). As he takes damage, he'll move faster and every so often he'll pause and glow before firing off a burst of magic, so keep up the Bubble Shield! After 4 successful Cannon Shots, it's finally over!
Hooray! You're the truest hero!
Starting with max items (everything x9), my final run to earn this achievement left me with 2x Bubble Shields and 3x Super Pike Ball/Super Monster Milk. So, yeah, plenty to spare!