Yup, Adagio is Ruby Sword’s ex, who’s flirty and teasy around him and Sunset because she semi-seriously wants him back, haha! Which can keep Sunset and Adagio from just being friends with how much it can annoy Shimmy…
 
And Ruby is deadpan and snarky to an almost chronic degree, so of course he loves puns like this… And the girls give him the response he bloody well earns. (I almost felt ashamed of myself when I thought of this joke, so Ruby more than deserves that slap xD)
 
And if you’re curious about his ringtone, it’s the beginning of this English cover of what’s probably my most favourite song/anime opening ever, and which honestly fits Ruby and Adagio’s relationship pretty damn well, especially when they were dating.
 
So expect to see more fun involving Ruby, Sunset and Adagio in the future, since their dynamic and interactions are too damn fun not to have brought to life n_n
 
Enjoy!