Can’t see. What is it?

I doubt they would have included this as just an easter egg.  With so much stirring in rumors lately, I would expect some announcements soon about re-releases of Xenogears in some form on Switch.

Wouldn't they have an Elly and/or Fei cameo then, instead of KOS-MOS? Ultimately a Xenogears port/remake would be up to Square-Enix and Xenosaga ports/remakes would be up to Bandai-Namco. Nintendo seems to have a closer relationship with the latter. 

Yeah I meant Xenosaga then.  I haven't had much experience with the series prior to Xenoblade, but a throwback surprise like this, taken into context all of the other retro revives we have seen lately, is likely going to end up as a port/remake announcement of some kind.

*Facepalm*

I want to say the title is due to a spell-check error, but... Now I am wondering if I should correct the topic title or leave it as is.

KOS-MOS from the Xenosaga series.
I think it’s likely just a Blade, there’s no need to have any direct story link. Even if XC2’s planet is within the Xenosaga universe.