In terms of two-handed weapons, you will find a lot of options as you progress in Zelda: Tears of the Kingdom, and the Strong Zonaite Longsword is an excellent option.
The reason being that this large 2H-Weapon is made from Zonaite and also has the passive ability to resonate with attached Zonai devices as well. This way it tends to increase some portion of its attack power.
In terms of base stats, the Strong Zonaite Longsword has a Base Attack of (10) in Zelda: TotK. Moreover, you can also fuse more than 70 items with this particular Longsword to create even more destructive weapons.
Some of the common places that you will stumble across this two-handed longsword will be the Thunderhead Isles and the Lanayru Sky. However, to get the Strong Zonaite Longsword from these areas you will have to do some exploration as well in Zelda: Tears of the Kingdom.
Strong Zonaite Longsword location in Tears of the Kingdom
If you haven’t discovered this weapon from the places mentioned above, then you can simply proceed towards completing certain shrines to find the Strong Zonaite Longsword in Zelda: TotK. These will include the following shrines:
You will be able to get the Zonaite Longsword after you enter the Zanmik Shrine and find the chest buried with orbs. So all you need to do next will be to open that chest and you will get your reward in Zelda: TotK.
Similar to acquiring the Zonaite Longsword at the Zanmik Shrine this time around you will get your hands on another one in the Sibajitak Shrine in Zelda: Tears of the Kingdom.
This time you will have to complete some tasks like aligning the first two pillars after which you can ascend through and find the chest waiting above. So by unlocking the chest, the Zonaite Longsword will be yours for the taking.
So these two shrines will defiantly guarantee you the Strong Zonaite Longsword so make sure to explore them and don’t miss these out in Legend of Zelda: Tears of the Kingdom.
Northeast side of Deep Akkala
Similarly, in terms of open exploration, you can head in the northeast direction from the Deep Akkala region in Zelda: TotK. After reaching the ledge you will see a tower across the water, so you need to access that tower from the rear.
To do this you need to ascend through the ceiling to get into the tower. Once inside you will find a Strong Zonaite Longsword inside so you can simply add it to your inventory in Zelda: Tears of the Kingdom.