[Chaos]

Normally, a person would only be able to cast a spell twice. (6m, or 7m if doublecast).

If you get refunded 1m per cast. You can now do 7m (any water spell) > 5m (any water spell) > 3m (Splash) > 3m (Anything that costs 3m).

This now, effectively, lets you cast 4 spells, instead of 2 (or 3 with splash). Not only that, but all have their damage increased by 40% (which is technically more, but still)

You only get momentum off a weakness proc once per round. You are still getting 3 spells, weak proc or no.

[Sarinpa1]

actualy, wrong,
different spells do refund 1M if used in succession

[Rendar]

Sarinpa1 is actually right here.

Each spell will refund 1m. So you can't doubletap the same spell and get 2m, but you can alternate between a bunch of different spells for the same effect.

[Kameron8]

i wonder if im missing something or if kams numbers are overexaggerated

The example numbers I picked have no relevance to the ultimate point, which was that you cast the same rotation of spells with an additional spell, and a 40% damage modifier. The only time the raw numbers do matter is when you address the amount of damage the sword does when you attack with it, when comparing damage with and without the river sword.

Assume for a second the river sword does literally zero damage. You spend three momentum, cast splash, then cast a water spell. In that turn, you have done more damage than you would have had you not invested the momentum to swing. Two water spells without 40% weakness will essentially never beat out two water spells with 40% weakness just because one of the two spells cast scales marginally better than splash.

From that point on, after dealing a variable amount of extra damage from sword + splash + water spell, you now measurably deal 1.4 x 4 water spells (assuming splash is present) each turn. A normal build not using the sword would deal 1.0 x 2 the damage of one water spell, or 1.0 x 3 if they use splash. To keep numbers fair, assume both use splash.

By the end of the second turn, the build with the river sword has done the equivalent of 5.6x the damage of one of their unboosted water spells. The build without deals 3.0x the damage of one unboosted spell. Without either build using splash, that disparity grows even larger. To me, an effective 86% damage increase at the minimum with a much larger gap at the maximum seems way, way more powerful than this weapon needs to be.

[Sarinpa1]

whew, got me worried there that I'm not abusi- ahem, using this properly, yes yes

The amount of damage you can pull is drasticaly higher than anything of similiar required setup, yes. (Aside from cinder+knockback/pull, anyway.)
Yet to absolutely kill this sword by making it impossible to trigger a weak message would hurt diversity in builds/aproaches to combat.
To summarize,
either require a build-up of the weakness by multiple hits in a row,
or consume the water weakness upon recieving damage from first water damage source. Both those will make it compare to standard equipment/class sets, be it excell + conversion gloves/collar, cindershit, classic MA autohits or combinations of thereof.

With the weakness consumed by first attack, I'd see it as you requiring to hit with subpar basic attack, then pulling one strong water attack, leaving you with 2m. If you managed to crit with the basic attack, you've got 3m, to either do a normal attack to apply weakness again, or whatever.

I'd say that's a good solution.

[Chaos]

actualy, wrong,
different spells do refund 1M if used in succession

Then it should be changed. I see no reason why you should be able to cast four spells just because you threw them all on the same weakness of the same target.

As for the sword:

1. If it's going to be a build-up, I wouldn't lower the cap below what the sword currently inflicts. A 12 Momentum requirement, alongside four hit checks (that require melee range), is a bigger investment than Intensify Cold.

2. Alternatively, with the current system, changing the effect trigger to 'On Critical' will make the effect harder to get off, and demand a much less lenient stat spread.

[Autumn]

Critical hits will always refund 1 momentum if the attack is made with a weapon that has not critically hit this round, I see no reason to change the weakness momentum gain considering there is also a resistance momentum deficit as well.

[Lolzytripd]

it should be changed to once per tome then, only fair/.

[Autumn]

it should be changed to once per tome then, only fair/.

That imples that everything that does x elemental damage comes from x tome.

[Sarinpa1]

It shouldn't and let's get back to the sword, rather than elemental momentum. The build up would be quite the investment indeed.
I'm not opposed to "On-crit." if the weakness remains 40%. However it will yet again become weak to the fatty crit-evade status-res glykins.