Beating Master Core is all about dodging and avoiding damage. I very nearly beat him on 9.0 without taking damage as default ROB, got hit by a few lasers from the shadow clone.
Master Hand/Crazy Hand
-Likes to start with Master Hand sweeping across the stage and Crazy slamming down in the center, so be careful of that.
-Generally just use Upair or whatever your character can. Fair, Bair, ect.
-Practice a few times on 6.0 (I think that's a max for Master+Crazy) if you have to, not even attacking, just dodging attacks for the time limit.
Master Giant
-Fully charge a smash while he transforms. This goes for all forms.
-Two hand grab attack: Sort of shakes for a few seconds, then two dark hands emerge from the body. Just jump over the one on the bottom, this is simple to avoid. While he's playing the animation that'd damage you if he grabbed, charge a smash.
-Large hand swipe: Hand moves upwards, then a small slash crosses the screen, followed by a large one. This can't be shielded, so you have to spot dodge. It's timing, maybe a half second after the small slash crosses.
-Energy balls appear above, grabs FD and moves it upward: You can shield a ball of energy exactly once before your shield is broken. Other than that just focus on staying out of their path: This move is short. Afterwards, use a smash as always.
-Scream: Not sure what block this, but sometimes your character goes flying and other times not. This is probably the single reason why you want to use a character with good recovery instead of little mac. Maybe shieldable, not sure.
-Gap appears in head, energy balls move across bottom: You can roll through the energy balls. This one can be tricky to avoid depending on the energy ball spawns.
Master Beast
-You can fit in two smashes between his attacks generally (character dependant). After that, just back off to avoid taking damage. This is the easiest form.
-Jumps up, slams down: Shield. Even if he lands on you it doesn't break shield I believe. Then smash him a couple of times.
-Slight step backwards (visual only, no actual movement), dark projectile shoots across ground, spikes appear when it hits. Shield.
-Arcs back somewhat, lightning comes down from sky. This breaks shields, so if you're shielding at the start just let go once it gets low and take the little damage. Otherwise, this is why you want to back off after getting your hits in. Charge a projectile or something while it's going on.
-Walks towards character, moves into background, bites: Shield it all. The trick to this guy is just shielding.
Master Blades
-Hardest form IMO, I find it easiest to hit him with upsmash or air attacks. Try to stand on the left edge or center of stage at most times.
-Slashes, 4 homing balls emerge: If you can absorb projectiles (ness/g&w) do that on these. Otherwise, just shield the slashes, hit a few times, then shield the homing projectiles.
-Slashes, 2 forward-then-back balls emerge: Absorb as said above if you can. Hit him a few times after shielding the slashes, jump over the projectiles/shield.
-Pulls swords back, follows closely, followed by massive combo ending in large slash: This is why you want to be on the left. Run to the right around halfway through the charge period and wait, if you can't get away than shield as long as you can then let the last few hits connect. This breaks shields if all hits connect. As the combo is ending, shield to ensure the final hit does not hit you. Then be very careful of the next attack:
-Small sparkle/sound effect, then big slash: Because he loves to do this after the combo attack. Shield it or spot dodge. This is probably what kills most people.
-Swords spread out, 4 slashes from various directions, final slash from above: All should be spot dodged. The final one can be shielded or spot dodged, but I think it breaks shields that aren't very nearly full. So practice the timing of spotdodges on this one. The final hit is definitely a killmove.
Master Shadow
-If you're not at like 100% this should be easy: The CPU sucks
-Very character dependant. Don't be afraid to camp and projectile spam, free damage is important.
Master Core
-Shouldn't need to be mentioned, but if you take too long he kills you with offwaves (which can be spotdodged if you feel like dancing with death or want to look really showy). There's 5 offwaves.
-Enjoy victory!
Hope it helps someone.
