From Eden Eternal Wiki
Ulta Hall is the five-man dungeon in the Valley of Kings. It is an ancient temple considered vital by the Church. Solemn statues line the area.
A gang of thieves known as the Carmela unearthed the ruins of Ulta Hall in search of the sacred sword hidden within. Ancient spirits warned the Village Elder of Garden about the bandits, and the Village Elder has now sent you on a quest to defeat the Carmela within the ruins of Ulta Hall.
Dungeon Length: Very Long
Ulta Hall is a difficult dungeon mostly because of its length and the common monsters around; the bosses are less of an issue. Teams attempting Ulta should have plenty of time on their hands before entering. Potions are also a must for everyone.
The dragons are probably the hardest part of this instance, littered all around the outer ring of Ulta Hall. Not only can their single-target damage reach up to 3000 per hit, they also have a double attack ability which causes them to hit twice 50% of the time, for damage up to a total of 6000. The easiest way to deal with them, is of course, to have a tank well above 6000 HP with good defense. This way you can just heal like crazy and probably manage to kill them without many problems. The option for groups without a well-geared tank is to kite them. Your tank will have to run in and get some initial malice from the dragons, so they stick to him. You then put a slowing effect on them and have your tank slowly walk them around the ring. If your DPS is decent enough, it won't take very long to get them down this way, and your tank hopefully won't die.
Kenny, the first boss, can be found in the southeast wing of the Ulta Hall temple. Kenny is a "tank and spank" fight - send in your tank and keep healing. He will start the battle with two minor guards. You can pull these before you pull Kenny, since the three aren't linked. You can also just AoE them down after starting the fight; this is not recommended if your healer or tank is under-geared. When Kenny reaches about 40% HP (estimate) he will start cleaving everyone in your group. The easiest way to handle this is to simply have everyone start using healing potions, and the healer just keep healing the tank as usual.
Dragon King Tiamat can be found patrolling around the outer circle of the Ulta Hall temple. Be careful not to get too close to him while cleaning out the other dragons, as he can show up anywhere around the circle. Tiamat is, much like Kenny, a tank and spank fight. In fact, you'll probably have more trouble with the dragon mobs before him than you will with Tiamat himself.
Gamera, the final boss, can be found in the southwest wing of the Ulta Hall temple. It is preferable to have a full-range team for Gamera, since he applies two debuffs to people within melee (AoE) range. The first debuff causes players to take damage when they hit the boss, and the second one causes players to heal the boss when they hit him. If you have any melee range players apart from the tank they're going to have to run in and out a whole lot and probably not do very much damage. Your tank must stop attacking whenever he gets a debuff, and your ranged DPS must stay out of the AoE range.