[Coda]

As I mentioned a few pages back, I've got Keeper of Gold on farm status, so I can get as many as I need without buying them. >.> My team is pretty close to failsafe unless I get super unlucky on heal orbs or screw up a combo after doing the leader swap, or get EXTREMELY unlucky and have a Keeper of Rainbow invade (which I've only seen happen ONCE).

KoG team:
Solomon Grundy - Folklore - Siren - Awoken Hera-Is (NOT uvo) - Awoken Noah
Best allies: Neptune Dragon, Andromeda, Water Twin Star Leviathan, Folklore, Antikythera, Goemon, Sarasvati, Princess Valkitty Heart (in roughly descending order of usefulness)
Alternatives: Antikythera works in Folklore's slot if you haven't evolved it yet, and you can use a second Awoken Hera-Is instead of Noah except it makes the last round less reliable.

Strategy:
This team is a long, boring slog, but it's pretty much safe. Use whatever skills you want during rounds 1-4 as long as you make sure you're above 50% HP when you take a hit. (Remember that rounds 1-5 have preemptives, so that means healing is of higher priority than dealing a finishing blow.) Ideally, you have enough water row enhances to make those worthwhile.

In round 5 (Keeper of Dark), charge your actives. (Use Siren if the alternative is dying.) When the boss gets below around 30% HP, hoard up a good combo's worth of water orbs, and wait until it hits you with Big Lance (so you're at 1 HP) and then use Folklore's active. Attack, and Keeper of Dark should go down. (If you substituted a second Hera-Is instead of Noah, make sure NOT to clear any heal orbs!)

Against Keeper of Gold, use Hera-Is's active, then Noah's active (or the other Hera-Is's). The damage from clearing the board full of water orbs SHOULD knock KoG below 50%. Use your remaining active skills to set up a powerful combo and KoG will go down.

If Keeper of Rainbow invades, just abort. You can't beat it.