Ginko's Ultimate Weapon - Persona 2: Innocent Sin Guides
Ginko's (Lisa) Legendary Weapon is obtained inside of the final room of the Abandoned Factory dungeon. Much like Tatsuya's Ultimate Weapon, this one won't be available until the very end of the game after you've gained access to the final dungeon. Since you need access to all 6 rooms of the Abandoned Factory to get this weapon you'll have to wait until you enter Xibalba (final dungeon) for the final Abandoned Factory door to become unlocked.
After you gain access to all of the rooms in the Abandoned Factory you'll have to unlock the Executive Suite. Once this is unlocked you will be able to unlock the Waste Treatment Plant which is the final room and where we'll obtain Ginko's Ultimate Weapon. For detailed information about how to unlock this room check out my Abandoned Factory Walkthrough.
Below is a quick list of each step involved in obtaining this ultimate weapon; for those who don't want the long walkthrough.
1. Read all 11 notes in the Abandoned Factory
2. Unlock the Executive Suite
3. Read the 2 notes inside of the Executive Suite
4. Fall through the hole in the floor of the main hallway (the location is marked on your map)
5. Read Note #14 inside of the room that you fell into
6. Return to Room #6 and encounter demons, form Pacts and learn a rumor about the Waste Treatment Plant at the factory
7. Spread the rumor about the Waste Treatment Plant
8. Enter the Waste Treatment Plant via the door in the southern portion of Room #6
Getting into the Waste Treatment Plant is going to be the hardest part of obtaining this weapon. Although it may sound like a real pain in the butt to gain access to this room it's actually not too challenging and should only take about an hour of grinding demons to learn the correct rumor. On the upside you'll also be able to obtain Tatsuya's Legendary Weapon while you're getting Lisa's. You'll get his inside of the Executive Suite.
Once you're inside the Waste Treatment Plant you'll have to navigate the catwalks until you eventually find a door that leads you to another room. Inside this room you'll find Reiji (pictured below), who is a character from Persona 1. Talk with him and you'll get Ginko's Legendary Gloves.
One of the unique things about the legendary weapons in Persona 2 is that you can make them stronger by learning rumors from demons and spreading them. After you obtain one of the legendary weapons in this game you'll start to see rumors appear in the 'give me information' dialogue about the weapon you obtained.
Each Legendary Weapon has a total of 6 rumors that you can learn and spread; all of these rumors cancel each other out so you can only spread one of them at a time. Out of all the rumors the best one is definitely "Legendary Weapon is Supreme", this will give your weapon a significant buff once you spread it.
Most of the other rumors will add elemental damage to your weapon and make it deal water, fire, earth or wind damage. Last but not least you have the rumor that your Legendary Weapon is inferior. As you can probably guess, the inferior rumor will lower the damage and quality of the weapon significantly.
1. Legendary Weapon is inferior
2. Legendary Weapon has the power of water
3. Legendary Weapon has the power of fire
4. Legendary Weapon has the power of earth
5. Legendary Weapon has the power of wind
6. Legendary Weapon is supreme
You may be thinking that this all sounds great but it comes with one catch that sounds worse than it really is. Demons can spread a rumor about your Legendary Weapon being inferior and make it a piece of crap... As I said though, this sounds a lot worse than it actually is because demons will very rarely spread this. The only way you can trigger a demon to spread this is if you cause them to be Scared 3 times during battle and they flee.
Even if you make a demon flee from battle it's still not a 100% chance that they'll spread this rumor about your weapon. If this does happen to you though all you need to do is spread one of the other 5 rumors about the weapon to cancel out the inferior one.