IMHO, Reuben could be of a significant help months ago when GTV core ran rampant or if they were not nerfed. Alas, Reuben is a bit late to the party by reason that Velurias potency, including their status ailments they cause, have been significantly reduced. Lady Loki would be good but I suggest to hold on to your rings. Who knows, you may get Black Knight next week during Avalon event, or Garnet and other legendary ninjas a week after Avalon, or new costume for your Marjana since Reuben would benefit from her elemental defense down as both would be at fast mana hitting the target and nearby.