pluralization

You could probably do it either way like with cactuses, cacti, and just cactus all being correct plural forms. Who knows how it works anymore. If we wanna be extra correct we could call them throwing stars, but that's surely out. So, I think it's all good with shurikens or shuriken, but I see lots of people ingame saying shurikens, so we could take that into consideration as well.

We also have a skill here named "Doppleganger" in-game, but someone was too upset with this since it's "Doppelganger" properly, and we use the proper version instead of what's in-game, so that's really nothing to go by. Personally if we're gonna go that route, I think it should be "Shuriken."

The doppelganger talk page looks more like they just never got around to changing it to doppleganger to me, or just didn't feel like it.

I could agree with that. Every form of "shuriken" on that page otherwise pluralizes it without the S..