Hey James, there's a way to get the strongest spear in tears of the kingdom. First you would need the trident from the Zora domain, then fuse it with a silver lynel saber horn. Equip the silver lynel trident, get a splash fruit and splash it on yourself. And you have the attack power of 152.
I found another thing Riju can do: While you activate her lightning power and the screen turns yellow she block instantly and after a block she attack so that make her more overpowered she even blocks while attacking and dodging!!