My concept of Lucina is a character all about mobility, mix-ups, and combos. As a woman from a post apocalyptic future, there is little elegance in her scrappy style of combat, but she still has some finesse none-the-less. Lucina is a fighter with average run speed, above average weight, a high initial jump and a poor double jump. Lucina is a fast-faller.
Before we begin, I should note Lucina has a special feature: "Exalted Right" is a passive quality unique to this fighter. Every successful strike to an enemy empowers her sword, gaining the trademark blue glow. At maximum power, her portrait is bordered with blue flame. While at full power, Lucina gains a small but noticeable increase to both movement and attack speed. Receiving damage or inactivity causes Exalted Right to fade.
Specials
Javelin
Lucina draws a javelin in her other hand, which functions as a unique weapon item and is aesthetically similar
of that seen in Awakening. Pressing B again while it's in hand throws the javelin, and you can hold B for extra power/distance. You can also throw it with Z just like any other weapon item, and while it's not as strong this way (just flips around in the air like any other thrown weapon), can be thrown in all directions. Her jab prods the lance, forward tilt brandishes it across, and forward smash results in a strong thrust with so much impact that it shatters the javelin.
If other fighters pick it up, they just swing it around like any other weapon, nowhere near as effective. Lucina can only have three javelins on screen at a given time.
Rout
This move causes Lucina to sheathe her sword and dash forward similar to Fox Illusion, but leaving a blue trail. What happens next is where this differs vastly.
Press A at the start will transist the move into a sliding kick. This stops Lucina on impact, pops the enemy upwards, and has little lag on hit.
Press B at the start to expend the Exalted Right effect and cut enemies on her path. Those caught en route don't take much damage, but enemies at the end suffer a blow of immense strength. If Exalted Right is at full power, this attack has vertical launch power akin to other lethal moves, like Luigi's Fire Jump Punch or Jigglypuff's Rest.
Lastly, you can press R to fake out, creating a blue trail but Lucina merely reappears at her point of origin.
Should no action be taken, Lucina will merely pass through enemies. This doesn't have much delay, but the blue trail sticks to Lucina for few seconds, and Rout cannot be used again until it's gone.
Counter
The trademark Counter mechanic breathes the spirit of Fire Emblem into Smash Bros! But this one is different. Countering while a Javelin is in hand will cause Lucina to throw it at full charge and at immense speed. If she is empty-handed, she instead tries to grab the attacker, with bonus reach compared to her normal grab.
Exalted Aether
Lucina turns as she throws her sword laterally into the air, and back-flips into the air to catch it, much like in
the cutscene. This does not hit enemies immediately in-front of Lucina, like Ike's Aether does, has much more horizontal distance than vertical, and Lucina does not naturally come down with an attack. Instead, at any point after Lucina has caught her sword, you can press B to come down with a sword plant to catch her foes off-guard.
Aerial
A corkscrew 360° swish of the sword that combos into itself rather well.
(forward)
Readies her sword before delivering a horizontal cut. A bit of wind-up, but a lot of power.
(backwards)
A backward kick followed by a followup horizontal sword slice.
Sheathes her sword and faces downwards before delivering a fast and deadly arcing slash below for a meteor smash.
Swishes her sword above before slashing in an arc. Multi-hit attack that lacks launch power, but has decent damage.
Ground
Delivers rapid horizontal slashes. Like other jab attacks, it automatically leads to an ender. In Lucina's case, it ends with a shoulder check.
(tilt)
Diagonal downward cut followed by an upward slash in quick succession.
(tilt)
Hand planted on the ground, she delivers a low horizontal cut with good reach.
(tilt)
Two quick arcing slashes above.
(smash)
Leans back before stepping forward and delivering a fierce thrust. Has immense reach.
(smash)
Does a fierce spin slash. It's not ideal for hitting low or rolling foes that are small in size.
(smash)
Does a short-ranged two-handed sword thrust, turns away from her sword and swings in an arc above,
like this. The initial thrust sets them up for the upwards cut.
(dash)
Vanishes and re-emerges a short distance ahead, cutting down those in her way.
Throws
Hooks her foes with the hilt of her sword.
(forward)
Kicks them away and follows it up with a slash
(backward)
Grabs them by the arm, spins them around once before letting loose.
Stomps the enemy into the ground, leaps into the air off-screen before coming down on them with her sword as they try to stand up. The best throw for damage.
Holds them up-high and delivers a sword thrust to send them upwards. Good for vertical kills.