It's inevitable for you to end up with duplicate Simulacra while carefully planning your pulls in Tower of Fantasy's Special Order gacha. These dupes are extremely useful in making your weapons stronger by increasing their base stats and unlocking passives.
What are the consequences of having duplicate weapons and Simulacra in Tower of Fantasy?
Duplicate Simulacra produce Fusion Cores specific to the weapons they're associated with. Echo's weapon is the Thunderous Halberd. If you pull a duplicate Eco in the gacha, you'll receive a Thunderous Halberd Fusion Core, which can be used to extend your existing Thunderous Halberd up to six times.
In Tower of Fantasy, how do you use Fusion Cores to advance weapons?
Open the menu by tapping the ESC key on the PC or the honeycomb icon on the phone's upper right screen. Select Weapons. On the lefthand panel, select Warehouse and select the weapon you want to advance, then click Upgrade at the bottom right of the screen.
It costs one Fusion Core for each weapon you're progressing, as well as some Gold to make one. You can also view the stat increase and additional passive on the left of the screen to see what changes your weapon will undergo. Each advancement will add a star to your weapon, and it can only have a maximum of six.
The more dupes you have, the stronger your weapon will be in non-competitive gameplay. However, this isn't necessary for non-competitive gameplay. If you don't want to six-star your weapons, you shouldn't.
Check out our guide on claiming a free SSR in the Tower of Fantasy Starpath Navigation event to get a powerful weapon for free.