An interesting hybrid, although it seems to be weak at control. Either your hot-blooded half will stall and hinder you, because you'll not have time to heal self and team, or you will be hampered by extra cold parts of yours. I think it could be better if you ditch Crystal Ice and Glacier (keep icewall as it's great for healing), max out Flash Freeze and maybe invest in Demolish to get more strength for landing Hypothermia and Decimates.

@vesperbot
I use regulate in the starting of the fight.
So, hot-blood is not a problem as only after 12 turns,i have to regulate...
And then, i constantly use decimate..
Crystal Ice gives me more power of Hypothermia and Vapour Cannon.
So, if on the enemy there are three debuff like 2 Decimate, Hypothermia. The enemy receives damage of 900 to 1200 every turn. And that's huge...

Any more suggestion will be welcome.

Thanks...

IIRC Decimate has a CD of 4, a little long. However you will have plenty of time to recharge these while you're healing your kids and using icewall. Regulate rocks, though it's the best move for a hot hydro at the very start (except FF/Regulate in case of someone strong).

DoT is not a strong side of Sonny 2, probably except for Psycho, with its Ultimatum/Sacrifice/Sacrifice/Psychopath/Epiphany/Free Will, then pwnage. 900 to 1200 is still pretty strong, but if you squeeze in Demolish, you'll get a lil more. And IIRC the only creature that requires DoTing him is Yosuke, I've blasted him with a hot hydro armed with FF, Demolish and Wreck/Decimate, sometimes even penetrating his 4k shield with direct attack :)

Hypothermia is only affected by Crystal Ice as initial strike, which is only 25%str+25%instinct, while 30%str DoT is not, which is stronger due to Lasting Pain. Vapour Cannon is a strong attack, but you'd better either whack with Decimate or FF or heal instead, except maybe those foes who disrupt, but then you have Restore to get focus. See, maxing Crystal Ice is 6 points, which could be put elsewhere safely. You have FF at 2/4, get it maxed and get a second slot - this is the best crowd control a hydro has. You have Demolish accessible, it gives power, why not getting that? You might decide upping Ice Wall, after all it does not affect DoT laid by you, but affects healing a whole lot.

In fact my cold hydro build rendered self as the following:
Restore 3/3 - we are a healer
Glacier 4/4 - this thing has the best side effect of all spammable special debuffs of a cold hydro. And having 2 of these removes the need of Vapour Cannon, which is rendered inferior.
Ice Wall 1/4 or better - we are a healer, and icewalled team heals better.
Flash Freeze 4/4 - crowd control.
Mind Freeze 1/4 early, 4/4 later - focus control, say whack specialist so he won't throw deadly debuffs.
Crystal Ice 5/5 - extra damage (and actually only needed against those who heal over time).
Cold Neurology 4/4 - we don't need much focus, so get some protection.
Ditched Shatter and ditched Guardian Form, and found having no need in either of the debuff attacks. However having Vascular Arrest proved worthy against Twin Guardians, when one was left in full HP I have used Ice Wall 4/4 and two Glaciers and a Vascular over him at once, he did 1 damage per shot but healed 1600/turn before vascular, and being protected 75% from my damage hurt.

@vesperbot
Thanks for suggestion.

I really don't like icewall.
I don't think icewall is a good option as icewall doesn't heal , it just increases healing. Restore heals some 3000 which is huge. So, there is no gain in increasing healing and just wasting 1 turn.

I have made vapour cannon stronger as i have to always keep focus above 100 as decimate scales with damage. Because sometimes , when flash freeze is not accessible , i use slam to stun target. So this causes loss in focus.

I like your Cold Hydro Build.

Yeah, Flash freeze is a good crowd controller. So , I agree your point.

Bringing demolish is a point.

Once,again thanks for suggestion.
Thanks for the help.
More suggestions will be appreciated.

I just restarted... for the 4th time, and I started just today with Hydraulic, but I can't find Shatter. I'm using the Shattering Beast build, but I'm not sure where to get the ability Shatter

Shatter is at lower left, requires level 10, deals some nice damage but it removes debuffs, and has a weak aftermath, you can as well go out with Glacier.

How do you beat nostalgia?

Also don't use frost/hypothermia to build the shatter debuffs.
THey both decrease speed, so if you get a double turn from them you'll lose a turn and won't get much out of fragile ice.
Glacier spam is nice for the stacking damage reduction.

Check out my guide, Sonny 2 Guide: Hydraulic Legend Run :D :D Search it on google :)

here's what I use:

2 flash freezes,
2 restores,
2 hypothermias,
2 decimates.

This set requires little to no focus, depending on how much you upgrade those skills, so you can fully upgrade cold neurology to add a bunch of defense at the cost of relatively useless focus. Also, restore heals focus as well, so you should not have any problem with that. the rest of your skill points, I would just use on passive skills, especially the crystal ice one.