Righteous
Righteous Arsenius Of Serpukhov
The identity of "Righteous Arsenius of Serpukhov" could not be confirmed by any independent source; likely an erroneous entry — possibly confused either with Bishop Arseny (Zhadanovsky), vicar of Serpukhov, a 20th-century New Martyr figure not yet formally glorified as a saint, or with a mismatched image belonging to an entirely different saint (Arsenius of Paros).
The card "Arsenius of Serpukhov" is not confirmed by any authoritative source (azbyka.ru, pravenc.ru, drevo-info.ru, days.pravoslavie.ru) as a distinct canonized saint. The only related historical figure is Bishop Arseny (Zhadanovsky), vicar of Serpukhov in the Moscow diocese, the last superior of the Chudov Monastery in the Kremlin, shot in 1937 — however he does not appear as glorified among the saints in the sources checked at the time this card was compiled. The attached image, meanwhile, is captioned in its original source as "Arsenius of Paros" — a completely different, well-documented Greek saint of the 18th-19th centuries (Arsenius of Paros, d. 1877, glorified in 1967), unrelated to Serpukhov. Given the lack of confirmation, the card is hidden from the calendar pending clarification of identity.