Wave 3:
Andromalius, 10m, 2 turns
Normal: Removes 20% of current HP, ignores everything like damage cuts
Rage: Removes 20% of MAX HP, ignores everything like damage cuts
Debuff resistance: Nigh-immune
Gauge behavior:
Trigger: First action: Cleanse all debuffs and applies debuff resist+ (cannot be Dispelled)
Trigger: Turns 10, 15, 20, 25 and 30: AoE nuke, damage increases with number of debuffs
She doesn't do normal attacks at all. Instead, every turn that she isn't Triggered or Overdriving, she will cast one of these AoE:
Attack Down (-50%)
Paralyze
Sleep
Charm (not particularly strong)
Blind
Overheat (damage cap 500, is considered a buff and therefore cannot be Cleansed)
Flame (damage cap 500)
Drowning (damage cap 500)
Poison (damage cap 500)
Corruption (damage cap 500)
All of these last for 3t. I sorted these in order of how problematic they are. Honestly? The first three are a complete game-over scenario. Thankfully, with a total of 10 debuffs and only 3 horrendous debuffs, chances are high you will rarely need to deal with them. Still, she is a much weaker version of GO Jack, which means that the clownfiesta she starts on her second turn CAN make the fight 100% impossible for you if the stars align right. So uh, good fucking luck.
Usually though, she isn't a big challenge. If you're on the weaker side, you can take things slow in the normal phase and Full Burst her once you reach Rage. As long as those three bad debuffs aren't up, Andromalius probably isn't a problem. Honestly, despite having almost triple HP compared to AQ5 (which have 7.5m and halve that due to debuffs = 3.75m HP), the damage output of AQ6 Andromalius is so mellow that she might be easier than AQ5 boss on average.