What kind of creature is the Sea God?

[Dark Knight]

I’m not exactly sure what type of creature it is. It’s not an apostle, yet it can create psuedoapostle-like beings and Gut’s brand bleeds to it’s presence. On top of that it can’t be a creature from the astral realm since it’s implied that it’s an ancient creature so it couldn’t have come from qlipoth or Griffith’s world merger. So what type of creature is it? The berserk wiki says that it gained it’s manifestation in the physical world after the world merger, but that makes no sense because the merrows have been fighting it for far longer.

 

[Aazealh]

I’m not exactly sure what type of creature it is.

It's a unique being.

It’s not an apostle, yet it can create psuedoapostle-like beings and Gut’s brand bleeds to it’s presence.

What pseudo-apostle beings? What it did was eat things to grow its "beard", including human-like tentacles it could use to lure more humans to their doom. Do note however that these are all just extensions of itself. As for the creatures living inside the Sea God, I'd guess they just had a symbiotic relationship with the big guy, like what actually happens in nature.

Regarding the Brand, well it bleeds when in proximity to evil. The Sea God was evil.

On top of that it can’t be a creature from the astral realm since it’s implied that it’s an ancient creature so it couldn’t have come from qlipoth or Griffith’s world merger.

It's absolutely an astral being. Its resurgence was possible thanks to the Great Wave of the Astral World. The Qliphoth has nothing to do with it. As for being ancient... Why is that a problem? The corporeal and astral worlds used to be fused together in the past before they were split. The merrows had locked it away a long long time ago.

 

[SpanishInquisitor]

I'm really tempted to say it was a big stupid jellyfish.

On a more serious note though, I guess it was a being similar to apostles and yet not, something shaped by the collective fears of humanity (The sea is actually very spooky, ever seen it at night?). So while it's not an apostle it still gets a cross-reaction with the brand, in a sense sometimes you are allergic to something but you get cross-reactions to other stuff.

Do note the brand acted up when detecting ogres and Kelpies so...

 

[Griffith]

A God... of, the... Sea.

I think it's pretty in line with the powerful mythical creatures we see elsewhere in Fantasia, it just so happens to be bigger, badder and of the ocean, literally an evil creature so big, powerful and pervasive it's like a god. Even though its design is original it could also be likened to legendary sea monsters such as the kraken or umibōzu. If I recall, one of the first things we see on their sea journey is a mythical sea creature like a giant sea serpent get eaten alive by an even bigger sea monster. If that's the setup, the Sea God is the extreme end of that progression.

 

[Aazealh]

On a more serious note though, I guess it was a being similar to apostles and yet not

No, it had nothing to do with apostles. Completely unrelated.

So while it's not an apostle it still gets a cross-reaction with the brand

The brand reacted to it because it was an evil astral being. Like you noticed yourself, the brand reacts to a lot of things, even to Flora, faintly, when Guts first met her.