Naturally, attempting to hunt Korrs with this base set alone will not be effective.

This is why we need to enhance these pieces. Everything you do to enhance your main set runes, elements, symbols, perfect bezels, plates, etc. needs to be applied to your underwater set as well. While elements and plates can be considered optional or postponed, but
I strongly recommend that you complete your runes and symbols. They are the foundation of your success here.
A Quick Side Note on Runes
For your helmet, you will need to insert a level 5 rune. This is because the required level 10 Elemental Sphere cannot be obtained from the Elfin Sanctuary at this stage. However, for all other pieces, you can and absolutely should use runes of level 6 or higher.
If you're on a tight budget, you can postpone investing in elements for a while, or even skip them entirely. However, symbols are non-negotiable.
Step 2: Choosing the Essential Symbols
So, which symbols are we talking about? We need a few specific ones, with the highest priority on your bracers, pauldrons, and boots.(Quick side note: Unfortunately, you cannot insert a symbol into the Gulldir.)
Bracers & Pauldrons: For maximum speed you will need the
Yt-Kor Symbol of Devastation in both of these items. With both symbols equipped, your critical damage will increase by a flat 10%. (For example, a 300 critical damage will become a 330.

)
Boots: For your boots, the essential symbol is the
Per-Flar Symbol of Will to Victory. When this symbol activates during a hunt, it provides a significant damage boost for 4 turns, drastically speeding up your kills.
The symbols for your other gear pieces are not as critical as these three. Therefore, your absolute priority should be upgrading these items first. For the remaining pieces, symbols that provide a +strength bonus are a solid choice. Such as
Cryph-Tarth Symbol of Sacrificial Power for Cuirass or
Tarth Symbol of Power for Chainmail.
Step 3: Character Development and Talents
Let's shift our focus to character development.
Korr has 5243 HP, which means landing critical hits is essential for efficient fights. We already increased our critical damage with the Yt-Kor symbols, but there's another way to boost it further: the Battle Art Code talent.
It is highly important to have this talent active up to at least
Battle Art Code, Volume IV. With that, you'll gain an extra 15% critical damage. When combined with the Yt-Kor symbols (10%), this brings our total bonus to a 25% increased critical damage. (if Battle Art Code V is activated, %30)
This means if you were hitting for 300 on a crit, you'll now be hitting for 375.
Step 4: Optimizing Your Combat Pockets
Now that we've secured our extra critical damage, we can move on to what's in our combat pockets. As I've emphasized throughout this guide, we need critical hits and we need them consistently. Therefore, you must be using Blood Elixirs.
If you have 8 pockets, a good setup is:
1x Giant Potion
5x Blood Elixirs
2x Life Elixirs
Alternatively, you could go with 6 Blood Elixirs and 1 Life Elixir.
Step 5: Choosing Your Superblow
I'll get to Blessings shortly

, but before that, let's focus on our final topic: Superblows. Which one should you aim for? Here, we have two options:
1-
Fury of Panther (the 4th level superblow)
2-
Great Thirst for Blood (the 6th level superblow)
My personal preference is Fury of Panther. The two biggest factors for me are that it only requires 4 hits to activate and it increases the final strike's damage by 35%. However, if you're struggling with survivability against the Korr, Great Thirst for Blood is also a viable option. Additionally, the stun effect from Great Thirst for Blood can sometimes lead to faster kills if it activates.