Of those 3, Anelia for sure. Themis is a Princess, sure, but the weakest one by far and Anelia is, from what I've read, one of the best units in the game for sheer damage output. Pirates have huge attack and range (slower rate of fire than archers though) and combining that with hitting 5 enemies per shot during skill, without the huge cost of mages, is just awesome. That said, Jerome is awesome too, I got him, leveled him up and he's able to generate UP faster than Katie due to Plats having quicker access to skill use than Golds (initial timer is lower even with same skill). That and his Awakening ability gives you +2 UP to start each map even if you can't actually use him there (maps like War of Magic this is a godsend, but really helps with almost every map that isn't meant to be laughably easy (lol at Low Cost Battle and its starting 100 UP))

If you use archers often, Spica Awakening priority is a MUST. 7% buff to their attack just by being in the team is incredible.

In general, for Awakening:
Team buffs (Spica, Katie, Adele, Sherry, etc.) > massive improvement to unit (Minerva shoots faster with her already massive attack, Marr heals a 3rd unit passively and her reduction to effects like the desert and poison maps improves, etc.) > Farming abilities (Celia > Monica > Robert > Cuterie imo, gifts aren't too hard to rack up, especially female ones) > making a unit stronger (Deine comes to mind)