First is a magical bolt that hits a single target in the front row. He has 3 attacks that he will chain randomly. He deals both physical and magical damage. The boss is Azakar, king of curses, a giant demon trapped in chains. The demon grave contains either a group of 6 of the demons you've faced during this dungeon or 50k Daru.
This area contains 2 groups of Incubuses (4 in each). This area contains the Roaming Summoner and the Pandora's Box (provides positive buffs only). Keep Suntoria up and your tank healed and you should have no problem. Deep Freeze and Incendiary Shot is a must for weaker teams. As always, the multiple buffs he casts himself when you reach his last HP bar cannot be removed by Scatter Shot. He uses the exact same attack pattern as before, except he is much stronger this time. The same boss you faced in solo dungeons and the secret area of The Void. This area contains 2 groups of Blue Demons (4 in each). Removing the buff is a must in Nightmare Mode. It can be ignored by stronger teams though. He uses this buff every 6 turns, but it is removable with Scatter Shot.
After halfway before his last HP bar, he will activate a buff that raises his attack by 100% and is stackable. He also has an AoE attack, which he uses every 3 turns. He deals physical damage, almost exclusively to a single target in front row. The boss is Nemrut, the firelord, a fire golem. They deal both physical and magical damage. The first area contains 2 groups of Ghastly Flyers (4 in each). At best you need 45k BR, more defense required for knight.2 archers with Scatter Shot and Deep Freeze (Incendiary Shot also useful).