Here's my analysis of the best legendary deniers out of the Sea book.

With deniers, the single most important stat is, without question, speed. If your denier is faster than your enemy's, you'll get to deny before they can. So, in order from fastest to slowest, here are the legendary Sea monsters:

1. Hydratila the Boltcaster; Blob
2. Hydratila the Riftmaker; Vodyanoy
3. Anton Acorne
4. Nidaria
5. Will "Razor Face"; Hydratila the Icebringer; Cavenfish
6. Commander Alvid; Sphyrnus
7. General Thetys; Thetys' Pet; Globrush; Famperium; Mystery
8. Watinhart; Varuna
9. Lotan; Lord of Atlantis
10. The Prisoner

Now this isn't where things end. We've got to look at skills, traits, and other things to figure out who is the best. And A LOT will depend on what monster the enemy is using too. Given the variabilities here, these are not necessarily in a strict order of ranking. One monster may be better depending on the enemies you're going up against.

We have to start with one of the best all arounders: General Thetys. She's obviously not the fastest of the Sea monsters, but she WILL deny almost every monster. Her Stamina Devourers has a 100% chance to drain the energy from the whole enemy team (at the expense of her own energy). Only a Super Attuned (or Hydratila) can do anything about it. She can fully recharge your whole team's energy, give a damage boost, and precision all in one go, has multiple freeze attacks. Lastly her Tough trait is one of the best. She's probably one of the most-used deniers in the game for good reason.

Cavenfish is another denial staple. He's tied in 5th for speed, is immune to freezing, can freeze, stun, and drain the stamina of enemies, and can give damage boost, precision, and energy regeneration to an ally. He's exactly what you want in a denier.

The superhero Sphyrnus is another denier that can do a couple of different things. He can freeze single targets and the whole team, he can stun a single enemy, he can drain 75% of an enemy's energy, and deal a little damage by way of bleeding. I find the best deniers to be the ones who have some versatility. Like the two before him, Sphyrnus is quick and always has another way of immobilizing an enemy.

If Varuna were faster, he'd easily be a top contender on this list. That doesn't mean he's a slouch. He's immune to stun, can freeze all enemies, stun a single target, and give stamina drain to all enemies.

Mystery brings a denial skill to the table few other Sea monster do: possession. He's immune to it himself, can also freeze, and drain the stamina of your enemies.

Anton Acorne is one of the fastest Sea monsters and his immunity to freeze is excellent. He can drain 50% stamina from all enemies, but has no other AoE deny skills. He can stun and freeze single targets, so if all you need is a single enemy immobilized (instead of an entire team), given his speed, Anton may need to be your go-to.

While Blob is tied for the fastest speed of Sea monsters, the only denial activity he can do is draining stamina. There's certainly good value in this, in fact, one of his skills drains 100% stamina from a single target. However, Blob also has a very high power and high attack values. He's a monster that really can have multiple builds and I prefer to use him as an attacker.

Vodyanoy also brings possession into the fight while being immune to freeze. And the second place in speed value is nothing to overlook. But outside of a single possession skill, Vodyanoy has no other denials. His other skills focus on regeneration, removing debuffs, giving damage boost, and the like. He's more of a supportive monster.

Nidaria is 4th for speed, which is a big plus and she's immune to freeze. While she can freeze and drain the stamina (50%) of single enemies, she can't do any AoE denials. Her damage output isn't particularly high, but she can cause poisoning and bleeding. In my opinion, she's more a secondary support/denier than a primary one.

The only deny skill Will "Razor Face" has is AoE stun. All his other skills revolve around stealing life and causing bleeding. One thing I do like about him is that he's one of only 4 in this book that isn't a water-type, but I think he ends up being a secondary attacker before being a dedicated denier.

Hydratila is designed as the perfect counter to Thetys and other deniers. He can freeze enemies, but isn't really designed for denial (although his Earth variation, Hydratila the Riftmaker, adds stunning to the mix). He's designed to counter the denials (by recharging team energy, giving freeze immunity, etc.).

Others:

Thetys' Pet, Globrush, Famperium, and Watinhart I think are all best used as attackers (Globrush and Watinhart both give weakness to their elements, allowing you to deal more damage).

Lotan and The Prisoner I just find very underwhelming across the board. Commander Alvid is a great monster who can deal all sorts of status effects, but isn't a denier. And Lord of the Atlantis is a supportive monster.

Again these aren't necessarily in any order, because who your best denier pick will depend on the opposing team's immunities. What do you think? Who is your favorite denier of the Sea monsters?

Nice I think blob is really good though.