Why do I see "Nobutoria" thrown around? Am I missing something?

Imagine Demon King Nobu just grab Caster Artoria and put her on the former's shoulder. Nobu doesn't want her to get tired out floating all the time. Nobu isn't as huge as Asterios so it looks awkward to onlookers. Caster Artoria doesn't complain but they did have to try out various positions after she almost slid off Nobu's shoulder and she protested Nobu keeping her secure with an arm. Door height isn't a problem as Nobu can shrink as she please. The Merlins mistakenly thought they're safe for Caster Artoria is preoccupied with Nobu. They forgot that Nobu never stops Artoria's ridiculous scheme to exterminate Sabers before. Not to mention Demon King Nobu is still nursing a grudge with female Merlin. They almost died for real if not for the Gudas' intervention on their behalf.

I used to think that when Master Artoria come to FGO, her class would either be Caster (terrifying mana reservoir) or Assassin (rarely on screen but always nearby in case Nobu needs her). Now I feel her more appropriate class would be Alter Ego. While Master Artoria knows no magecraft just like her King of Knights self, the circumstances are different. She is in a flipped situation where she's not in charge as the head or the powerhouse. Is she's good enough to be Nobu's partner, her inner qualities definitely are not to be disregard. Yes, I still believe she'd use Nobu's sword as weapon but her style would resemble Ryougi Shiki's. She surprisingly gets along well with all the other Nobus aside from Kaiser Nobu (arguably her original Nobu), including the chibi ones. Due to Chaldea unable to house them, the chibis will either stay where they are or invade Chaldea on their own accord. Whether it's a successful kidnap attempt (rescue mission to them) or not depends on how Master Artoria handles the situation and if the Nobus decide to not exterminate them. The Artonobus would always be safe from them however. Okita doesn't know how to deal with her.