Hi! I'm an old player that's returning, and I'm stuck on the battle with King Deisus. I'm able to get him down to about 70% health but then my team gets completely wiped out. I thought the fight would be easy as my pets are all a higher level than him but from what I've seen things have changed since I've been gone and I'm not sure what I should change.

For reference, these are the pets I have in my party. Any help with this would be greatly appreciated!
https://www.sylestia.com/view/pets/?petid=3042490
https://www.sylestia.com/view/pets/?petid=3042524
https://www.sylestia.com/view/pets/?petid=3201162

1. Two tank elements (Shadow (Generalist/Survivalist tank), Earth (dedicated tank)). Recommend you pick which one you prefer for tanking style and swap the other to Light (party healer) (or water (more tricky to use party buffer with a move that can shield+heal a teammate- they grow to fit the position much better at later levels).

2.
Shadow pet's equips are mostly Strength type instead of int types, equips are low rarity.
Replace with epic or legendary lv50 Illusionist (int/agi) gear if tank.
If swapped to Light element, either epic/leg lv50 illusionist or lv50 evoker (int/dex) (or both, whatever)

Earth, equips are half int types, and low level
Replace with e/l lv50 Assassin (str/agi)
If swapped to water, either that or Myrmidon (str/dex)

You could also change whichever is swapped to a non-tank element to 2 offense profs

Fire is equipped with entirely Str gear, also all low level.
Equip with Evoker, make profs both Int.

3. did you do all the seals correctly? Doing the seals makes Desius weaker

Edit: I managed to get one of the seals and defeated him! Thank you so much for helping, I really really really appreciate it!!

Ooh, thank you for the help! I've updated some of their relics/armour/accessories/proficiencies as well as switched my Shadow pet to Light, hopefully they're ok!

I can't remember if I did the seals or not so I decided to go back and redo them just in case-I tried to do the Seal of Alacrity with my Light pet as he has the highest agility (based on a guide I found) but I'm unsure if it did anything as the text pretty much said 'nothing happened and you're not sure if it worked'.