Lachesis' Rule

A Lachesis' Rule is a Staff found in Golden Sun: The Lost Age. It is dropped by Mad Demons in Anemos Sanctum, although the odds of receiving it are very slim. Being a Staff, it can be equipped by Jenna, Ivan, Sheba, and Mia. It can be bought for 21700 coins and sold for 16275 coins. It increases the wielder’s attack by 177, making it the strongest Staff in the game in terms of attack power.

Lachesis' Rule's Unleash effect is Apocalypse, which activates at a rate of 40% (notable, since most Unleashes activate at a rate of 35%). It converts all damage to Jupiter damage and attacks with an additional 125 attack points, which is higher than any other Unleash in the game (though it still pales in comparison to the damage multipliers of some of the game’s strongest weapons, like the Sol Blade and Excalibur). In addition, it sometimes curses the target, automatically killing them after approximately 7 turns.

Although powerful, Lachesis' Rule may not see much practical use seeing as it is acquired so late into the game. Anemos Sanctum can only be entered once the player has collected all 72 Djinn, making it the final (although optional) dungeon in the game. This makes the already risky Curse inflicted by Apocalypse rather trivial: by this point the party should be strong enough to defeat most enemies before the Curse could complete its work. Also, although unlikely, Jenna and Ivan may have already aquired the stronger Tisiphone Edge, capable of doubling or even tripling the damage done. If this happens, the only Adepts who would need this weapon are Sheba and Mia.

In Golden Sun: Dark Dawn
It makes a return in the third instalment. Like in The Lost Age, it is found late in the game and is a rare drop item. The Red Wyvern in Crossbone Isle drops the Lachesis' Rule. There is a 1/128 chance of it being dropped but will increase to 1/32 if an offensive Jupiter Djinni is used. It gains three new unleashes: Critical Move, Double Attack, and Spiral Assault.

RNG Method (Golden Sun: The Lost Age)
Enter the Anemos Sanctum (requires all 72 Djinn). Save game. Reset. Wait until you encounter a Mad Demon accompanied with something.

1st Round (big arrow on Mad Demon):

Felix casts Mother Gaia

Jenna casts Aura

Sheba casts Tempest

Ivan casts Tempest

2nd Round :

Felix attacks other monster

Jenna copies

Sheba unleashes Whorl (Mad Demon)

Ivan casts Plasma (big arrow on Mad Demon)

Atropos' Rod vs. Lachesis' Rule
At first glance, it seems that Lachesis' Rule is the game's most powerful Staff, with Atropos' Rod coming in at a close second. However, upon closer inspection, it's possible to say that Atropos' Rod is the stronger of the two. The most obvious reason for this reversal of power is in their Unleashes: Atropos' Rod's Unleash, Life Shear, has a small chance of instantly killing the target, which is a huge advantage over the time-consuming Curse caused by Lachesis' Rule's Unleash, Apocalypse.

Also to be taken into consideration is when these two items can be obtained. Lachesis' Rule can only be found in Anemos Sanctum, which can't be entered without all 72 Djinn. This requires the player to collect all 28 Djinn in Golden Sun, transfer their data to Golden Sun: The Lost Age, and then locate the remaining 44 Djinn. Because of this, some players may not even reach Anemos Sanctum, let alone get a Lachesis' Rule. In comparison, Atropos' Rod is fairly easy to obtain, requiring little more than access to the interior of the Yampi Desert Cave.

This isn't to say that Lachesis' Rule doesn't have it's advantages over Atropos' Rod. The most notable advantage is that Lachesis' Rule has a higher attack rating, which can make a huge difference since the characters that can equip these weapons usually have low attack ratings. Also to be taken into consideration is the elements of their Unleashes. Life Shear is of the Mars element, while Apocalypse does Jupiter damage. This makes Atropos' Rod an excellent choice for Jenna, whose high Mars power would make Life Shear even stronger, while the same idea makes Lachesis' Rule ideal for Ivan and Sheba. However, Jenna and Ivan may find the attack multiplier of the Tisiphone Edge to be stronger than either of the Staffs (although it is worth mentioning that their Venus power does have an impact on the damage dealt), leaving only Sheba to take full advantage of the Unleashes.

In the end, which Staff is stronger is largely a matter of personal preference.

Cultural references
In Greek mythology, Lachesis is one of the three Fates. Lachesis was the weaver; she and her sisters appear within three days of a baby's birth to decide their fate. Lachesis measures the thread that is woven by Clotho, and decides the destiny of the being.

Each of the Fates has a weapon named after it in The Lost Age: Clotho's Distaff, Lachesis' Rule, and Atropos' Rod.