Description
Fate/Stay Night vs Dies Irae
Both are old and sadistic magic users who are considered witches by others (in Medea's case, she is actually a witch) who rely on magic instead of close combat.
They both go by other names (Caster and Malleus Maleficarum)
They are both considered to be the magic specialist between the superpowered people (Servants and the LDO)
Both participate in a secret war (Holy Grail War and the LDO activating the Swastikas) in order to get their wishes granted (in Rusalka's case, it's more of a group against one guy instead of a Free-for-all)
Their backstories involved gestión betrayed by their loved ones (Jason and Rusalka's husband) and going mad
They have the ability to alter reality in a small space (Her Territory Creation and her Briah)
They have control over another superpowered being (Medea has Assassin, (and Archer and somewhat Saber) while Rusalka has Tubal Cain) who are considered different in comparison with the others (Kojiro in Fate's World never existen and Tubal is an amalgamation of corpses instead of an individual)