Once you enter into the illusionary realm, you will have to relive your fight with Waterblight Ganon, however you will be reduced to using only the following items…
- Lightscale Trident
- Ceremonial Trident (x2)
- Silver bow (Arrows x10)
- Level 2 Zora Armor Set
- Hyrule Bass, Hylian Shroom, Fleet-lotus seeds
For this fight, conservation is key to victory, so utilization of your runes and accuracy with you items is paramount.
During this phase, Waterblight Ganon will perform either a sweeping attack with his spear or a thrust. Both of these attacks you can dodge and perform a flurry attack. This flurry attack will in consequence stun Waterblight Ganon. Stunning this boss as much as possible is critical to success. For this phase, to spare weapon durability, you can optionally use your remote bombs to deal direct damage while Waterblight Ganon is stunned. While Waterblight Ganon is not stunned, use your Lightscale Trident to deal damage wherever possible.
During this phase, Waterblight Ganon will begin to fly around the room making it impossible to deal direct damage with a melee weapon. However, you can still stun him with the 10 arrows at your disposal. Whenever possible, use your arrows to score critical head shots on Waterblight Ganon, effectively stunning him. Then, deal direct melee damage while he is stunned. As this phase progresses, Waterblight Ganon will move around the room more rapidly, making it more difficult to deal direct damage when stunned. To help alleviate this, place a Cryonis block in the center of the room. This will help you travel around the room when you successfully stun Waterblight Ganon. Also note that Waterblight Ganon will begin sending ice blocks your way. Use Cryonis to destroy these blocks as they appear.
Once you run out of weapons, your best tactic is to begin throwing remote bombs at Waterblight Ganon. Additionally, you can use Stasis on the last ice block that he sends at you. This will help stun Waterblight Ganon and help you eventually defeat this difficult foe.