[Tactician] Divinity: Original Sin 2 Devourer Dragon - Simple No Cheese Strategy

This is a fight where with a bit of planning and strategy you can beat it without resorting to any cheesy tactics. My approach does not require any particular builds or items - the only requirement is that your team has enough damage to take the dragon down within one turn. It's not a demanding requirement I'd say, given that this is end game and there are so many broken combos in the game.
The strategy is:
1. Start the conversation with any of your characters; just before the fight begins, throw all your buffs to it. Living on the Edge is a good buff here to stop it from dying. DON'T start the fight yet.
2. Move all other characters to the top corner (high ground). Put everyone on stealth.
3. Start the fight. The character who did the talking should start first. Throw all the damage you have with it.
4. For all the other 3 characters in stealth, delay their turns. Devourer and their lackeys will only target the first character (if within range) or do nothing (if out of range), since they can't see your stealth characters. The first character won't die (Living on the Edge) so there's nothing to worry.
5. After the enemies have all taken their turn, your last 3 characters in stealth will now have the whole turn to themselves. You have high ground so just nuke the Devourer down. Easy! The lackeys will disappear after the dragon is dead so you don't need to worry about them.
Note: in the video, there's a bit of variation where my first character (who did the talking) delayed its turn too. The reason I did this is because I want the other characters to remove the dragon's magic armour first so I can debuff it with Bleed Fire and Burning to maximise fire damage for my 'first' character.