From Eden Eternal Wiki
Baram's Chasm is the first dungeon in Avila Volcano.
While not the geographically largest map, nor the most populated with monsters, the bosses in Baram's Chasm make it a challenge to complete and parties may cycle through several different arrangements looking for the right way to defeat them. However, the dungeon gives great experience and is a wonderful option for acquiring extra EXP during some of the toughest levels in the game to reach. The first thing to keep in mind is to use a Bard as a healer here; the boss AoEs here kill all the party, not just the tank, and a cleric cannot heal all the players at once fast enough to counter these foes. The dragons grouped together in the paths are formidable, so do not fight more than two at once.
Quiller is the harder boss because of the amounts of damage he can do. He will probably kill the healer first, leaving the tank and DPS to wither away. Only a Bard's Music of Life skill can reliably prevent this. Quiller also may spawn with a 70% additional HP buff, so it may be a long fight. Be watchful and hit him with everything you've got, be it stuns, sleep, or continuous DoT stacks.In general, Miller should not be a problem after conquering Quiller. He can heal himself for a set amount, though, and stack a buff that makes him more and more powerful. Stunning him as this skill flashes will make it fade and prevent it getting too out-of-hand.