Lucky Seven

Lucky Seven is a weapon in Xenoblade Chronicles 3. It is a legendary sword forged by seven Swordsmithpons in the past that is used by Noah. It took at least seven years to make it.

Appearance and properties
Lucky Seven appears as a thin sword with a black hilt with violet glowing lines and a circular hole near the pommel. Most of the time it is concealed in a sheath resembling a large red sword with a Flame Clock meter near the pummel, which changes into the Ouroboros symbol once Noah is freed from the Flame Clock; while sheathed, it is known as the Veiled Sword. Whenever Noah pulls Lucky Seven from its sheath, his left arm is covered in a glowing armored gauntlet that compromised of the sword's sheath.

Lucky Seven's blade is forged from seven different types of steel, and is capable of damaging even a Ferronis. Lucky Seven is one of the few weapons capable of destroying Flame Clocks.

Story arc
Early in the story, Lucky Seven is concealed in a red sword, called the Veiled Sword. The sword itself first appears in a flashback in which Riku presents Noah Lucky Seven after his sword was destroyed by Garvel. Riku reveals that the sword is so powerful, it can pierce the armor of a Ferronis, before he asks Lanz to strike it with his Shieldblade, cleaving it in half, and leaving Lucky Seven untouched. Noah initially declines until Riku suggests to hide it in some form of disguise: the Veiled Sword.

When party fails to destroy Colony 4's Flame Clock in an attempt to cut off healing for Moebius K, Noah remembers Riku's wisdom about Lucky Seven and decides to draw it for the first time to finally destroy the Flame Clock and kill K. From this point onwards, Noah would often use Lucky Seven to free Colonies from the control of Moebius throughout Aionios.

Noah later uses Lucky Seven to destroy Colony Lambda's Flame Clock during the party's battle with a mudpuppet of Isurd. At Engardo Pass, just as P and O, were about to detonate themselves, via annihilation event due to Interlinking too long, Noah uses Lucky Seven to destroy the cliff that they're standing on, sending the chimera Moebius plummeting into the Great Sea, allowing the resulting annihilation event to go off safely. During the party's battle with the Queen of Keves, Noah considers using Lucky Seven to break her barrier, despite Lanz's objection, due to potentially killing the Queen (although it was later revealed that she was an imposter).

During Mio's Homecoming at Agnus Castle, Riku takes notice that Noah still haven't used Lucky Seven's full potential, reminding him that today is the day of need. Noah finally unleashed Lucky Seven's true power after his battle with N, drawing an enlarge version of the sword from his Ouroboros core to defeat him. When X sets the fake Queen of Agnus upon the party, Noah uses the sword to destroy the machine and its Flame Clock, freeing everyone at the Castle.

Gameplay
During the battle with Moebius K, Noah unlocks the Infinity Blade, in which Noah briefly unsheathes Lucky Seven to deal a large amount of damage, ignoring defenses.

During the battle with the Queen of Agnus, Noah unlocks the Unlimited Sword Talent Art which unlocks the power of Lucky Seven, changing Noah's (and by extension his s and s) for 90 seconds: his class becomes Lucky Seven (Attacker), Lucky Seven (Defender), or Lucky Seven (Healer) depending upon whether his normal class is an Attacker, Defender, or Healer.

In all cases, Lucky Seven's s are Gravity Blow, Dimension Ripper, and Tachyon Slash. Its Master Arts are Power Raiser and. Lucky Seven's Talent Art is Final Lucky Seven which inflicts the Smash Combo with an AOE and Pierce. After N is defeated, the Master Art Harmonic Wave becomes available. If Noah Interlinks while Lucky Seven is drawn, the Ouroboros Talent Art Origin Blade becomes available immediately.

Trivia

 * While sheathed, Lucky Seven resembles the Monado from Xenoblade Chronicles and Pyra's version of the Aegis Sword from Xenoblade Chronicles 2, continuing the trend of Xenoblade Chonicles' protagonists swords being red.
 * If Noah fights Kevesi or Agnian soldiers while Lucky Seven is drawn, he will use the blunt side of the sword instead of the blade end.
 * Interestingly, Noah will use the blunt side of the sword against Z∞.