2nd act spoilers, that huge boss on water

[黄豆腐]

What level should you challenge it ? Sprong

I checked the guide, the pictos it drops seems overpowered able to play two turn in a row

[Jan]

I did Sprong in Act 3, much easier.

[Hatman]

I can't tell you a level, myself i was way overpowered already when i did him. But his attacks are pretty easy to dodge/parry. More a question of patience than level.

[Crimsomrider]

One can beat him in ACT II without a problem if dodging/parrying isn't an issue, although it takes 15+min around level 50.

Otherwise doing it in ACT III will be much easier and faster.

[prusswan]

it is all about dodge and patience (especially the last phase if your health/defence is not enough to survive any hit)

[Inf]

I recommend skipping him until Act 3. Anything with an HP bar that doesn't move noticeably when you throw a bunch of 9,999 damage attacks at it is meant for Act 3.

Not that you can't kill him - I know you can do it. But, if you do it'll make all of Act 2 trivial. I killed Sprong and the Noir on the beach and it made everything easy.

[Evilsod]

Plenty of people have beat him in act 2, but it sounds like a hell of a slog and you need to be incredibly consistent with dodge/parry timings.
Unless you specifically want the challenge of beating it earlier on, do it in act 3.