Would seem a bit odd for a family from a land with an Egyptian theme to have their sword be a German design.
Yeah, but it seems like the 20 Families are going to be kind of oddly mixed and matched with their weapons, from what we can see.
I mean...why does the "Rimoshifu" Family have Longinus? "Rimoshifu" is...vaguely Chinese-ish. With "shifu" meaning "master". And "Rimo"...possibly coming from the Tibetian or Indian for "mountain"? So, the name translates to "Mountain Master", probably. And Longinus is the name of a Roman soldier from Christian traditions. There's NO connective tissue, there. If Oda was being "culturally" consistent, the Xiantian Axe would have made more sense to be the Rimoshifu Family's Weapon. Even Killingham's Kirin Fruit has more Chinese-inspired origins!
And the Shephard Family getting Gram? Gram is from Norse Mythology. "Shephard" is really more of a English word. And given the whole "sheep herding" sound of the name, THIS is the family that you'd probably expect to get the Christian-themed Longinus. If only to tie everything together with Jesus, as he "tended his flock". Plus, again, Sommer's Thorn Fruit would just work better, thematically, with Longinus. Given the whole "Jesus wearing a crown of thorns" thing. (But, maybe Oda was specifically warned away from doing too many Christian parallels in the story by his editors, given how the west can be, so he had to move things around?)
So, I don't know if there's actually going to be any rhyme or reason for which family gets what weapon. All these cultures and names might just be mixed together.
Which...might actually be thematically relevant, up to a point? In the past, all these cultures used to be mixed together. And they only got separated and categorized as being distinct after the fact. Kind of like how, over time, divisions were created between cultures and races. Like the rift that formed between Humans and Fishmen, or Long Arm and Long Legged Tribes. Everything used to be one culture...until everyone got separated, by time and by the sea. I could see Oda maybe playing a bit with that.
...Or it's just rule of cool. And he thought Killingham looked cooler wielding a spear, rather than a axe. It's hard to tell what Oda's highest priorities are, sometimes. Sometimes, he has really deep thematic reasons for his choices. And...sometimes not.
And perhaps even more, from Joyboy and who knows who else...
Well, we KNOW that there are also Divine Weapons on the table. So, Weapon Piece is only just getting started!
Like the War God's Hammer, Ragnir. And Nika's Sword and Shield. (And maybe his Spear, if Oda isn't retconning that into someone else's weapon via the Chapter 1138 Mural)
I WOULD say that I'd expect that ALL the Gods probably had at least one weapon of their own. But...we really haven't seen Zaza the Rain Goddess use any sort of Weapon, yet. So...maybe some of the Gods didn't have Weapons? Who knows?