Sea Dragon King - Mythical Plus

Volsung did Power Suction on me over and over above 90%. Not just one time.

hera-is did absolute zero on me and i did NOT die. bug?

ive been grinding this dungeon for the last 7 weeks send help

Used the same team for Volsung, Linthia and Gainut:

Odin w/ Breath of Creation skill inherited for spike
Avalon Drake
Archangel Michael w/ Astray Mist skill inherited for defense break
Archangel Michael w/ Space-Time Tuning Circle Wd/Fr inherited
Moon Flower Artemis w/ Force inherited for delay (finally found a use for Hydra)
Awoken Liu Bei friend w/ +297

Awakenings are important for auto-heal, but level and skill level are less important. Should have one orb changer ready to provide green orbs to quickly burst Flr 1 & 2 (usually my friend's Liu Bei). My cards had an insignificant number of + eggs.

Flr 1: Burst with green row
Flr 2: Burst with green row
Flr 3: Stall for skills. Burst with orb change when ready.
Flr 4: Burst with green row
Flr 5: Stall for skills. Burst with orb change when ready.
Flr 6: Can stall if needed by matching 4 poison orbs, but I usually just burst with orb change.
Flr 7: Astray mist defense break, plus burst with green row
Flr 8: Attack with green since defense break carries over
Flr 9: Stall for skills. Orb change and burst when ready. Breath of creation makes it a sure thing.
Flr 10: Stall for skills, but move forward with Michael's skill, not Astray Mist being ready. Whittle down if bored. Burst before 30%.
Flr 11: Use Force for delay. I tend to use Avalon Drake, Michael + Breath of Creation to drop HP to 1.

So I have been trying to beat this solo for a while now, and just did with this team. I believe you can change a few subs but this is what I used. All hyper maxed.

Remeber to Heal often. This team his minimal RCU.

Moonlit Feline ACE w/Chaotic Call...orb change wood. fire. dark.
Ult. Vishnu
Verdandi
Reincarnated Ra to kill PreDra
Echidna to use on the last Floor.
Moonlit Feline Ace w/ orb change, wood. fire. heal.

Flr 1: stall if possible, or sweep.
Flr 2: sweep
Flr 3: hit below 75 % then kill. Allows for stall.
Flr 4: sweep, stall if possible
Flr 5: Kill in two hits, orb change if needed.
Flr 6: Hit below 80% then kill.
Flr 7: Sweep
Flr 8: Use Ra
Flr 9: Hit below 75% then kill, or sweep
Flr 10: Sweep using orb change
Flr 11: Use Echidna, Orb change. Should have plenty of turns to kill. I did it in two turns.

Hope this helps with some options to win.

They changed latent invades to Water Resist in the coin dungeons as of today.

This team worked surprisingly well considering the relatively low HP. Granted, the only times I took damage were the pre-emptive strikes. But with only a couple of exceptions you should be able to take a hit from everything before the Super King Dragons. Manage your HP, make consistent 7+ combos and you'll do fine. I'm sure there are other monsters that could be substituted for Liu Bei and U&Y. Off the top of my head Kaede would probably work instead of Liu Bei and any multiple TPA water monster with a skill bind resist could replace U&Y. You will definitely want to have 5 skill bind resist awakenings because you're screwed if Hera-Is skill binds you right before you face the boss. Good luck and happy farming!

Reincarnated Bastet with Super Power Hymn inherit (add 3 green and 3 dark orbs)
Restrained Dragon Hero, Liu Bei (love that triple TPA)
Vigorous Hunt Gods, Umisachi & Yamasachi
Reincarnated Neptune
Reincarnated Ra
Reincarnated Bastet with green orb change inherit

All max level, all max skill, both Bastets, Neptune and Ra +297. All latent awakening slots filled with either time extends or Penta. Neptune had two Skill Delay Resists.

Floors 1-4: Green TPA and as many combos as possible
Floor 5: Blue and Green TPA and as many combos as possible but make sure to heal to full. Use the first turn to heal and second to kill if need be.
Floor 6-7: TPA and combos
Floor 8: Ra
Floor 9-10: TPA and combos. I recommend using a skill to activate Bastet's 2.5x multiplier.
Floor 11: Neptune, use whichever skills you need to in order to create enough green orbs for at least two TPAs and as many combos as possible. It was an easy one shot kill since Neptune's poison takes care of that pesky last HP due to Volsung's resolve.

I used this team for both dungeons, based off a Blonia team that Mantastic used:

Main:
Blodin(Sitri) / Blonia / Ryune / V.Orochi / Mori

Alt:
Meridionalis / A.Isis(Lumiel) / Sarasvati / Sumire / Sumire

F1-F2: 1 row will sweep
F3: Get the dragon below 50% for blue sky fall buff, then kill
F5: Use Sumire/Ryune if there are not enough hearts to heal up for next floor
F6-F7: Use Active if needed, 1 row and TPA should kill
F8: use Isis' Lumiel to kill
F9: Use active to kill
F10: Use Meri's active to guarantee for combo guard, 1 row should kill
F11: Use Orochi to delay first, then use Blonia to nuke down, then ping him with 1 blue match