This Seeking Tech guide will explain how you can beat Fire Dragon Mauna in Metaphor.
This optional battle can only be triggered in the Nord Mines. You won’t be able to fight the dragon if you sneaked past it. Before the fight, make sure you have plenty of MP.
If you need to recover your MP, then you should equip the hero with the Mage Archetype. You should then backtrack to the area south of the Magla Hollow. Attack the three moth and five teeth enemies there to regain your MP in this location. You can then go to Magla Hollow to respawn these enemies. Repeat this sequence until you recover your MP to full.
When it comes to fighting Mauna, make sure you have a Mage and Seeker. These Archetypes should move to the back row at the beginning of the fight. The Mage should use Blizz to exploit the Dragon’s weakness. The Seeker should guard and only heal when necessary.
If you have enough MP, then you should be able to outlast the dragon.