[Agema]

LA Rlyeh's sea domination may be much overstated.

Jomon has some pretty brutal underwater units, well capable of giving Rlyeh a bloody nose. LA Ermor could at least make Rlyeh pay by fielding its own vast armies of freespawn chaff, even if they are a little feeble underwater. Mictlan should be able to field some brutal thugs and sacreds.

However, there is absolutely no way LA Atlantis can't take out Rlyeh underwater if they want. In fact, if the LA Atlantean player is in a game with LA Rlyeh, I expect he will have prepared a bless specifically against Rlyeh.

The key are Assartuts - add an S bless to make mind blast not very effective, an E bless so they can kill all day without tiring (their armour is low encumbrance), and an N bless just so they're really hard to kill. They are astoundingly destructive.

Nearly all the Atlantean troops massively outclass Rlyeh's freespawn. Ice Guard (also low encumbrance for the protection) will make mincemeat out of them, the others less so, although you will run into fatigue problems if you're that badly outnumbered. What's even better, Atlantis gets reasonable astral mages underwater, which means Antimagic for even less worry from mind blast. Besides, just cart around an Angakok with +MR and put him at the front, to be overtaken by the army - let's see all that mind blasting wasted on a regenerating unit with high natural MR (plus Amulet of magic resistance, astral bless, iron will) Finally, think Angakok thugs - you can do a lot with a few of them.