Update from me...lv23 for everyone, B8F, right before the boss.
Some 2nd stratum related spoilers regarding enemies, FOEs, and slight story revelations forthcoming here.
[spoiler]Quite a few fun enemies here to contend with. The fun stopped at High Onneps though. They're basically the new Great Lynx/Largebill/whatever really high ATK normal enemy for the 2nd stratum.
To make it even more painful, they start showing up in pairs on B6F.
I thought it couldn't get worse...then I saw a trio of them on B7F. Yeah right I'm not going to even think about fighting 3 at once

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B8F...besides yelling at the upgraded version of the High Onnep, I managed to survive against most mobs down here. Still need to farm Iron Turtles for Century Shells in order to unlock a new armor.
FOEs...Abyssal Death, besides having a pretty cool name, started out rather tame. Just normal attacks that were easy to patch up from via my Monk or item usage from my Buccaneer.
Me : "When do I start getting scared of what you can do because I'm unimpressed at this point...OH CRAP!"
That'd be me after A.D broke out its special skill, an attack that hit everyone. Everyone survived of course, but basically anyone not named Zero (my Gladiator) could not take more than one of those or they'd die.
Got lucky with nobody getting killed in this fight...and to boot, getting its conditional to unlock a rather powerful crossbow for my Arbalist.
Fast forward to B8F and confronting someone. Said person makes me fight an Abyssal Death. I'm not 100% prepared because I had no Amritas, though I was nearly at full for everyone. Zodiac's maxed out Dark Ether saved my rear end here, allowing me to spam Party Heal and make it to the end.
Tonight, I'll probably get to see what the 2nd stratum brings forth in terms of a boss.[/spoiler]