@Rigel31415, Ottar saw Leon to use his "attack" at some point, only then could he make comparisons between the two, but the question is where? In the coliseum? I don't think so because such waves that endanger level 6s like Mia would kill the spectators.

That led me to think that it would be more possible that Ottar had seen it against Leviathan where Leon could use it at full power without causing collateral damage; also since Ottar mentioned that his attack was not as good as Leon's right after seeing the effect it had on the lake, I inferred that the water was a comparison factor.

It's only circumstantial evidence so I should have mentioned it in the previous comment, however I see it as the most likely scenario, although of course, it might have been otherwise.

@Longhatruong, you're relating Leviathan to Amphisbaena, the latter is an amphibian, that's why it has one level on land and another different one in the water, however, Leviathan is a purely maritime monster (if its representation is faithful to its mythological version), for that reason I didn't see any sense in considering that it would have different levels depending on the environment because it's a monster that will always be in the water.

Even so, you could have a point, but in the opposite sense to what you're suggesting, let me explain, it's not that Leviathan is stronger in the water (it's always in the water) but that the adventurers are weaker in underwater fights, although thinking that they would lose an entire level for being under water I think would be too much. But the postulate is valid in any case.

At this point we enter the realm of speculation but I think the fight against the monster was from "land", I seem to remember that the school district, before being a school, was a warship created specifically to confront Leviathan on the high seas, so each combatant would be in their element, the monster in the water and the adventurers on "land", so each would have his real power during the fight.

@Leinad91

Amphisbaena, the latter is an amphibian, that's why it has one level on land and another different one in the water

Are u sure about this? I don't remember Amphisbaena being an amphibian or that it can move on to land. In the anime, it doesn't even have any legs iirc. And I dont think Amphisbaena has level 6 in the water and level 5 on land. It is always a level 5 but fighting it in the water is as hard as fighting a level 6.

it's not that Leviathan is stronger in the water (it's always in the water) but that the adventurers are weaker in underwater fights

This is exactly what I means. Amphisbaena( and likely Leviathan) would pose a threat one above their true level because adventurers have to fight them in their aquatic terrain.

I seem to remember that the school district, before being a school, was a warship created specifically to confront Leviathan on the high seas.

I don't exactly rmb this detail, but I seriously wonder what makes Leviathan can not flip the school district or just sink it from under the water. Well, about this, we can just wait until Omori showing us the fight.

Yeah, Amphisbaena doesn't move on land. From what I understand the thing is that as an aquatic monster its mobility while fully submerged is way higher than when it is just moving around in the surface of water. Kind of like Marie who was obviously nowhere near Bell new Level 4 in terms of power but while swimming outsped a running Bell.

I don't know if DM19 mentions it but in SO13 it is explained the School District was originally made to fight the Leviathan and it served an important role in it. As for the Leviathan being unable to sink it or anything like that, well who knows, but if it was made specifically to fight it it's not really rare to think they figured out a way to avoid that.

@Longhatruong, thinking about it, I think you're right.

The fact that Amphisbaena is level 5 on land and level 6 in water is inaccurate; Aisha explained it like this: it is considered level 6 by the guild but its real status is level 5, it is given a higher level due to the difficulty of facing it underwater.

What led me to consider it an amphibian was that it was able to get out of the water when it jumped to the ceiling of the 25th floor to launch itself like a kamikaze and make the floor collapse; which means that it can get out of the water but that doesn't make it an amphibian. Sorry for the inaccuracies, I read volume 14 years ago!

That being the case, the parallel you are proposing between Amphisbaena and Leviathan could well be true, if it were the case that adventurers who are not experts in maritime combat had to face it underwater, Leviathan could have a great advantage just like the one Amphisbaena has (one level). But remember that there is the Diving development ability that might well mitigate the effects of the aforementioned advantage, therefore, I would believe that based on this DA it is determined for each particular case how much disadvantage it will have in underwater fights.

There is also the fact that the combat itself could be amphibious, as was the one against Amphisbaena where the Hestia team fought from "land" while the dragon was on the surface of the water. In the case of Leviathan, it could have happened in such a way that those with the Diving AD fought in the water and those without it fought from the deck of the ship, so Leviathan's advantage would not have been constant or universal throughout the fight.

For these reasons, I believe that it should have been a level 10 in order to represent a great challenge for a team with 1 level 9 and perhaps some pseudo level 9s as well, since as I explained previously, it cannot be generalized that the monster had a 1 level boost over all its opponents.

If they have defeated a level 10 Leviathan and even level 10 Behemoth like you said before, wouldn't you think the Hera captain would have been able to level up to level 10 from those feats? The same goes for other members of Zeus/Hera Familia, Maxim would have went up to level 9. Zald/Alfia and other executives would have went up to level 8 respectively.

The fact that Behemoth/Leviathan have been defeated make me think those 2 monsters are probably level 9 with some gimmicks that making them close to a level 10 threat at most. Ofc, I also wouldn't deny that they could well be level 10 because Omori love making battles look impossible to win just for some epic moments, and he just didn't think too deep about what Zeus/Hera can get after beating 2 level 10 monsters.

About the Diving DAs, I will be damned if more than one of Zeus/Hera execs have it. At most, I can imagine one or two guys from Poseidon Familia, who are high enough level to contribute to the fight against a level 10 Leviathan like you said, having that DA. Rmb that if the threat is level 10, even a level 7 would nearly be a fodder. Only the executives can join such battle, and I highly doubt Omori equipped them with Diving DA.

Don't think I haven't wondered why they didn't level up; Alfia and Zard were at the limits of their respective levels and defeated some legendary monsters! If completing one of the "three great quests" isn't enough to level up, then what does a level 7 have to do to level up to level 8...!? It's Omori's thing, it's not the first time a character does something that should level him up and he doesn't do it and it won't be the last.

I have serious reservations about Behemoth and Leviathan being level 9 because of the following analogy: Ottar is tied with Balor, if the others (Hogni, Hedin, Allen and the Bringar) help him they would win immediately, so if Leviathan was tied with the Empress of Hera and the others (Alfia, Zard, Maxim) help her they should win without problems. Reason that leads me to think that the monsters should have been at least level 10.

As for whether they were level 10, the level 7 adventurers would be fodder, not necessarily, Ouka, Mikoto, Welf and especially Bell could be of some help against Black Goliath after all, despite a difference of 3 levels.

Despite everything, I cannot categorically affirm that your proposal is incorrect. The idea that they were level 9 but had tricks that increased their difficulty also sounds plausible, in the case of the Behemoth we know for sure that it had its trick (the poison) and regarding Leviathan, well, perhaps being in the open sea it would have had much more mobility than Amphisbaena had fighting in a cave and that gives it a great advantage against adventurers fighting from the deck of a ship.

Finally, I mentioned the Diving AD to emphasize that underwater combat would not give him a universal advantage over all his opponents, especially if some of those who had it were level 6 or 7. I mentioned it because you were giving too much importance to the monster's underwater advantage :P.

Don't think I haven't wondered why they didn't level up; Alfia and Zard were at the limits of their respective levels and defeated some legendary monsters! If completing one of the "three great quests" isn't enough to level up, then what does a level 7 have to do to level up to level 8...!? It's Omori's thing, it's not the first time a character does something that should level him up and he doesn't do it and it won't be the last.

I have serious reservations about Behemoth and Leviathan being level 9 because of the following analogy: Ottar is tied with Balor, if the others (Hogni, Hedin, Allen and the Bringar) help him they would win immediately, so if Leviathan was tied with the Empress of Hera and the others (Alfia, Zard, Maxim) help her they should win without problems. Reason that leads me to think that the monsters should have been at least level 10.

As for whether they were level 10, the level 7 adventurers would be fodder, not necessarily, Ouka, Mikoto, Welf and especially Bell could be of some help against Black Goliath after all, despite a difference of 3 levels.

Despite everything, I cannot categorically affirm that your proposal is incorrect. The idea that they were level 9 but had tricks that increased their difficulty also sounds plausible, in the case of the Behemoth we know for sure that it had its trick (the poison) and regarding Leviathan, well, perhaps being in the open sea it would have had much more mobility than Amphisbaena had fighting in a cave and that gives it a great advantage against adventurers fighting from the deck of a ship.

Finally, I mentioned the Diving AD to emphasize that underwater combat would not give him a universal advantage over all his opponents, especially if some of those who had it were level 6 or 7. I mentioned it because you were giving too much importance to the monster's underwater advantage :P.

Somehow, I'm seeing duplicate reply.

Indeed, I used to hope Zald and Alfia are fresh new level 7s, leveling up after beating Behemoth/Leviathan. Thus, Ottar can fight Zald with beastification. How wrong I am.

I admit I'm not sure. I agree that being level 9 makes them sound a bit too easy and being level 10 would makes them sound too hard.

And I only said if the monsters are 10, even level 7 would nearly be a fodder. That's clear with your black Goliath example. Welf, Mikoto, Bell could only contribute because of magic sword, magic, and Argonaut. Even Ouka was out with only one hit. Yes, they can contribute, but they basically can not join the fight because getting hit even once most likely result in their dead. Someone with 3 levels below their opponent can only fight with either super strong magic or a skill that close the level gap, as Zald and Alfia did. I'm not dismissing the Diving DA to be useless, but for it to truly be a game changer in the fight against Leviathan, I do believe the one who has it need to be the level 8 or level 9, which I don't imagine possible unless Poseidon Familia having a level 8.

You are right that I'm giving too much importance to the underwater advantage because I really think that's the case just by imagine it. Part of it is because I'm thinking the Leviathan is just a level 9 as well instead of level 10. Anyway, I just wait for Omori to prove me wrong like Hestia's Familia battle.

Amphisbaena very much does move on land, what are you guys smoking? It is described walking around multiple times in Volume 14, it literally climbs up the waterfall, the usual strategy for fighting it is to lure it on land and into the caverns away from the water.

Oh yeah, and it's specifically drawn with four legs.

Read 13/14 again.