Marth (SSBU)/Neutral special

Overview
Marth's neutral special, Shield Breaker, is, contrary to the name, rarely used to actually breaks shields. Instead its primary use is to force an impulsive response out of an opponent in fear that their shield could get broken.

Regardless, as the name suggests, Shield Breaker breaks shields relatively easily, even if it isn't fully charged; an opponent's shield that has taken even a small amount of damage, often from being poked by down tilt or an aerial, or has been shielding for a while can easily have their shield broken. As a result, the fear of Marth using Shield Breaker on them can force them to react and be open to being punished. The common responses are:
 * spot-dodging, which Marth can quickly close in on or attempt a quick Shield Breaker if they habitually re-shield.
 * roll, which can also be closed in on or easily punished if the opponent accidentally rolls into Marth.
 * jumping, which can either be challenged directly with an aerial, or punished on landing.
 * attacking, which can be challenged by Marth's other quick attacks or avoided by a roll, spot-dodge, or simply being out of range.

Shield Breaker can be used for ledge trapping opponents who habitually shield. Down tilt, forward smash, and his aerials already cover hanging, jumps, and some double jump attacks leading to rolling, ledge attacking, or shielding being the only available options. The lattermost option is easily ruled out by the threat of a shield break, forcing the other options or punishing those who hold shield. Shield Breaker can also be spaced to punish ledge attacks, though tilts or smash attacks are a safer option due to Shield Breaker's relatively slow speed.

In the event Shield Breaker breaks a shield, Marth can setup the opponent for an easy kill by pushing them closer to the edge (though not too far to push them off and get them out of shield stun). At mid percents it can easily KO with the tipper. It will do 1.15× damage if it hits the opponent's head, making a properly angled and spaced Shield Breaker even more potent.

Shield Breaker also has interactions with Marth's aerial momentum. When charging Shield Breaker, Marth loses aerial momentum. This makes it difficult for Marth to employ flickshot Shield Breaker as a way of covering space. On the other hand, when released in the air, Shield Breaker instead increases Marth lateral momentum, with a fully charged Shield Breaker granting the most. Varying how much it is charged can allow for mixing up the opponent or potentially countering their edgeguard. Against characters with several edgeguarding techniques, such as, it can be nice to have another option for lateral movement mix-ups besides using the double jump.

Hitboxes
The hitboxes with the "shield breaker" effect have a damage multiplier of 1.15×. However, they can only strike opponents' head hurtboxes, and unlike the move's damage increase by charging, this multiplier functions as a "damage taken" modifier (like the 1v1 multiplier), so it has no effect on knockback dealt or damage to shields.

The move triggers a Special Zoom if it breaks a shield with any of the hitboxes.

Not fully charged
The hitboxes' damage can be multiplied by up to 2.2× depending on the move's charge, for a maximum of 17.44% or 19.62% (respectively) right before reaching full charge. More specifically, the damage multiplier is equal to. When fully charged, the hitboxes are instead changed directly with no additional damage modifier.


 * }

Fully charged

 * }

Timing
On frame 12, the aerial version adds forward momentum of 0.5 (in units per frame) if not fully charged, and 2 if fully charged.

!Grounded !Aerial