Conveniently enough, this is a good month for Thunder SRs. Thunder Nyarlathotep (limited) provides C-frame -15% def debuff (and atk debuff too, so depending on what you need/have, you can move Cyclops to the bench in certain encounters). Gryla (the freebie from Yule Goat raid later this month) is pretty solid for a raid hime. 1000 HP/6 turns party heal and an A-frame atk debuff that also works specifically as an atk buff dispel (oh hi there Rahab reprint at the end of this month).

If you have a lot of jewels saved up, it wouldn't be a bad idea to take a chance on Thunder Nyar. Then save some to take a shot at Thunder Aphrodite next month.