Heeey, what a shiny marble. Mystia's hat: "Π― ΠΈΠ΄Ρ, Π²ΡΠ΅ ΠΌΡ ΡΠΎΠΆΠ΅" ["I walk (go), all of us too"]. Cursive in russian and calligraphically done right for a japanese artist. But had to stare for a while to grasp the script on multiple posts.
Hmmm, that is rather ambigous. How about something like "I go to war, we all go to war." ? Since Mystia is here to get revenge for Rumia.
As full as I found - "Π― ΠΈΠ΄Ρ Π²ΡΠ΅ ΠΌΡ ΡΠΎΠΆΠ΅ ΠΈΠ΄ΡΠΌ" and not a single word about "war" ("Π²ΠΎΠΉΠ½Π°").
30-40 seconds ago looked closely at one corner to finish the phrase. Have to admit, that I was like Reimu - "beat first, think later". In russian it can be finished context wise, a rather abstract one. As said in trns note, that verb have wide range of meanings and the phrase don't have any additional words or specific grammar to pinpoint context. I'd give meaning "I live (exist), as we all live (exist) too."
Edit n+1: just noticed - bottom of dress have same phrase looped.
Updated
I walk, all of us walk too.
Gotta closely inspect pool for that hat to get full phrase.
Verb "ΠΈΠ΄ΡΠΈ" has wide variety of meanings, but basically context revolves around "come", "walk", "pass by", "happens" etc, so its hard to say what it's meaning context wise in this short phrase.