If anyone wonders how to get new 100k slow stacks achievemet

[pkkp]

New upgrade to phantom needles, new helmet and new cape are quite helpful.

If you want to be even more sure then there are also slow upgrades to transfixion and ring blades, goo shoes and rat ring. Also cleric and cleric mark have effect on hit chance in base stats.

[Moldredd]

Also the new Broker's Cape is useful for that. Shouldn't give too much trouble on Agony with a fully Slow Inducing build with the Cleric. For abilities, it seems that Frost Avalanche's Quick Freeze will be useful as well.

[MESeele]

Screw the needle upgrade. Transfixion fully upgraded shoots 3 sprays almost 360 from the character. Cleric also has tons of effect chance boost traits. Pretty sure Transfixion also has effect chance traits. Easy.

[Nihilum]

I did mine with transfiction and frost avalance without much hassle as well

[Vallahga]

I just did a try with transfixion (both upgrades, full effect and multistrike trait path) and frost avalanche (w/ quick freeze), cleric's mark + medusa mask on Frost Caverns reaching agony V.
I only reached ~60k slow stacks.
Also the transfixion achievement wasn't reached either (~60k too)
I previously tried with the cleric on Viaduc and roughly same abilities and I was far from the mark on both achievements.

Maybe it's easier and other levels (more enemies) ? Maybe I missed a trait somewhere to allow more stacks on enemies at the same time ?
I'll try the needles upgrade but I'm not confident it will be sufficient.

[Nirvash]

If you use Gorgon mask and do Viaduct, when you get to the point where the invincible ghosts start closing in, you can basically infinitely apply slow to them over and over as long as you're keeping track of the other surrounding enemies. Transfixation, Frost Avalance, and Ringblades all have upgrades that give them slow. So if you work that into a stand-still build, you can just run along the bridge until you find the ghosts and just stare at them while your other weapons attack behind you.

[MESeele]

Viaduct has annoying enemies that don't swarm to you (gargoyles circle from a distance, soldiers patron without a care for you)

I feel like Ice Caves and Viaduct have way worse enemy density compared to just the first 2 areas. Just do the first area in Agony. Don't use your main weapon. For good mobs just stand still.

If you can really can slow the ghost army, that works too. You could just farm them.

[Vallahga]

Ok I did a run in ember grounds, Cleric with cleric's mark, first levelep up needles and avalanche, then transfixion.
Validated the slow achievement 10 minutes before the end.
Validated transfixion achievement right before the final boss despite unlocking transfixion upgrades pretty late.

So I do not know what was the most impactful between
- doing the run in the ember grounds (rather than viaduc and frost caverns)
- Using Cleric + cleric's mark (for lots of bonuses in effect chance)

Anyway, thanks for all the advice.

[Shin-ou]

Can't get it due to PC limitations. My PC nearly crashes from the sheer amount of projectiles and puddles making the game go at 2FPS before the game ultimately crashes

[Lordbufu]

Norseman frost focus, with cleric trait, and all slow gear. Hilarious build imo, certain mobs and bosses almost come to a full stop (as might your fps when going for fully upgraded Frost Avalanche), once your debuffs start to kick in with the right traits.
Damage is a bit low, but man that was good fun :P

Also Rats count as summons, if you consider the summon spawn traits you get when you pick Astro Orbs, and consider the gloves with summon spawn bonuses ....

[Chippawaffen]

sweet this helped me get both in one run since i was dreading the rate i was going. Archer with cleric trait started with phantom needles into transfixion then yoinked the pain bringer rat ring from a red chest then followed up with frost avalanche and blade rings.

appreciate yall

[KaizenSoze]

Finally got it thanks to all the advice in this thread.
Agony Viaduct
Cleric with Northman mark
Goo boots
Medusa mask
Ice ring
Rat ring
Broker's Cape

In order:
Frost Avalanche
Hail stones
Trans fixation

Got the achievement at about 5 mins from the end.