TLDR:

• Frozen Legion possibly (i.e. not confirmed or hinted at by anyone at GGG AFAIK) scales similarly to Shockwave, gaining CDR and EAD
  • please please please remember to cross-check when gem information is dropped and do not take this as gospel - it is hypothetical although at least an educated guess
• It's a decent 6th link for average attack speed builds
• It might be mainable if your weapon is exceptionally slow, but Heatshiver is likely the most straightforward way to scale it for now. 4 sample builds to get your own theorycrafting started, although those are not guides
• Not the best thing since sliced bread but might be useful if you intend to start it because new shinies :sparkle:.
• Long post ahead: read at your own risk

I've seen some sporadic interest in Frozen Legion but nowhere near as much as Volcanic Fissure, since the skill is a lot weirder. Among other things, there's two common refrains when declining to speculate further on Frozen Legion. First, we need 20/20 info as the gem looks a bit shit at the moment, and second, it doesn't seem worthwhile to run it in a second 6L which a) implies the use of a 2H which isn't meta now and b) adds a lot of possibly unjustified socket pressure to a build.

Gem Level Scaling

But putting those two refrains side by side is quite suggestive. Looking at its role as an on-demand single target boost, it functions fairly similarly to Shockwave Support, which is socketed in your main 6L, in adding an additional attack to your damage rotation rather than amping your main skill itself. Both skills even eventually scale to 6 charges, after a fashion.

Looking at Shockwave's numbers, Shockwave starts with 0% CDR and 160% EAD at level 1, scaling to 38% CDR (gaining 2% per level) and 270% EAD (gaining 5.25% per level) at level 20. That's remarkably similar parameters to Frozen Legion which was revealed as having 0% CDR and 170% EAD at level 1.

That suggests (subject to confirmation) that Frozen Legion will scale in a similar manner, which tentatively puts its level 20 stats at 38% CDR and 270% EAD at level 20. At those numbers, that actually puts its EAD on the higher end of attack skills. The highest EAD for regular melee attack skills is Ice Crash, at 350% EAD, so on an attack-to-attack basis alone, Frozen Legion is actually on the higher end of the scale.

(Vaal Burning Arrow and Vaal Ground Slam have slightly higher EADs, at 400% and 375%, but both are Vaal skills (i.e. uptime-limited) and the former is ranged.)

As for the CDR, that moves Frozen Legion's CD from 0.8s to 0.57s at level 20, shortening the recharge cycle from 4.8s to 3.42s. If you include the 0.7s default cast time, that's 5.5s to 4.12s - almost under the duration of a cyclic buff like Chieftain's Ngamahu, Flame's Advance.

I have to repeat again - this is purely speculative. It may be premature by a couple of days, but since it's an educated guess, it might get us an extra couple days' worth of theorycraft time on probable information, especially if you intend to start the skill. It also goes without saying that if the gem doesn't scale with level, the numbers really don't shake out well.

Additional scaling

On top of CDR from gem scaling, CDR is also available on items (belts and Eldritch boot implicits, probably), and possibly from alternate quality. In addition, the fact that FL is a skill gem rather than a support also means that it is eligible for helm enchants unlike Shockwave, and it is possible that some enchants will deal with cooldown.

Looking at a conservative 10/15% CDR on enchants (Warcries have 20-30%, Seismic has 10-15% IIRC), 15% from belts, 10% from boot implicits and 10% from quality, that's another ~50% CDR you can get, which pushes the cooldown of Frozen Legion to 0.42s, for a recharge cycle of 2.52s (or a full damage cycle of 3.22s including default cast time). That is super comfortably under Ngamahu, Flame's Advance buff cycle, even allowing for imperfect casting (i.e. not immediately off cooldown); that could allow you to cheese in a couple damage spikes while you have the full advantage of 100% phys as fire.

Default Quality

Wild guess, but default quality is likely something like 10% increased damage.

Separate 6L or 6th link

A very rough sample of SSF 2H melee builds suggests that 2H builds tend to average around 3~ APS. On the Frozen Legion CD numbers above, adding about 1.5-2 APS of an above average attack looks like a pretty good deal, being about 50% more damage on average.

For comparison's sake against some non-Awakened gems:

• Multistrike is 40.5% (1.22x average attack damage * 0.8x attack damage penalty * 1.44x attack speed bonus)
• Melee Physical Damage is 34.1% (1.49x damage * 0.9 attack speed penalty)
• Ruthless is ~32% on average (98/3)

So 50% more damage is actually pretty competitive against other supports from a purely numerical perspective. For that reason, I'd suggest that Frozen Legion is actually best placed as a 6th link, not as a separate 6L. That means you aren't locked in to a 2H weapon, and have some flexibility in picking weapons (e.g. with Frostbreath for a Heatshiver setup).

Of course, the question is whether an extra 10% more damage is worth having to specifically cast another skill, based off a stat (cast speed) that most attack builds scale at most incidentally via Frenzies if at all. That's one major way in which Frozen Legion differs from Shockwave; the latter is passively triggered, while Frozen Legion needs to be actively cast. 10% more damage might not be worth it for min-maxers who would accept that as the penalty for automation vs e.g. Shockwave, but it makes it justifiable for people looking to play the skill for stylistic reasons.

Where/when to use Frozen Legion

Because of the relatively fixed cooldown time (as opposed to much more scalable attack speed), the relative power of Frozen Legion shifts depending on the attack speed of your weapon. High attack speed builds like Berserker and Raider would get less comparative advantage out of Frozen Legion; being able to hit 6APS+ drops Frozen Legion's contribution to 33% at best if not worse on an APS basis, even before accounting for the need to add cast time. You're really probably best off with a 5th support in that case.

However, since the cooldown mechanic of Frozen Legion is both a floor and a ceiling, it's interesting for slow builds as the power disproportionately shifts. In a "best case" scenario of using something really slow like Marohi Erqi, Frozen Legion can grant something like 194% more damage at level 20 without additional scaling alone, simply because your attack speed is so slow that the cast and cooldown time of Frozen Legion is so much faster in comparison. It might even be worthwhile to run Frozen Legion as your only 6L in that scenario, since a fixed cast time of 0.7s is better than trying to hit with an attack time of 1.3+s.

(Rough maths for those interested - comparing Frozen Legion as a 6L for an Ice Crash main link using the new Marohi Erqi:

Marohi Erqi is 932 average damage, at 3.5x Ice Crash EAD = 3283 damageOver ~4.5s damage cycle, 3283 * 0.75 * 0.7 = 4.5 = 7756 damageFL over the same cycle, 932 * 2.7 * 6 = 15,098 damage15098/7756 = 194% more damage)

That said, Chris has said that the statues take your attack speed, and we don't know what happens if you try and recast Frozen Legion while a previous statue is still attempting to execute an attack. There's also the potential problem of enemies running out of the attack radius of a really slow Frozen Legion attack, so while the numbers look interesting, it might be fraught with practical problems in play.

In practice, Frozen Legion is probably at its best in a happy medium of slower than average builds, where it would represent a decent burst spike even accounting for the cast time. Things like Pulverise, Melee Physical Damage, or the Mace mastery for double damage help that along; usually you'd not want to use those scalars because of the attack speed tradeoff, but given you're not actually executing the attack, slower attack speeds might become palatable. Something like the attack speed of a Debeon's at 1.44 APS would make Frozen Legion a 104% more damage multiplier, which is clearly superior to any possible 5th support.

Possible builds

I've come up with 4 builds which use Frozen Legion: Normal Chieftain, Slow Chieftain, Raider, and Inquisitor. Broadly, within the parameters subsequently explained, all builds approximate between 500k and 900k DPS, with Frozen Legion prospectively forming either all their damage (in the case of the Slow Chieftain), or between 44% to 86% more damage based on the main skill used. I don't believe there's anything that is too far off base, but in the event I've mixed something up between theorycrafting four builds at the same time do let me know.

Build baselines

All of them are SSF and league-start oriented. Two of them use the Heatshiver unique, which while unique, isn't particularly rare, so I think it's just barely acceptable to use them. The tree is set to lv90/91 (113/114) skill points, assuming you kill all the bandits, gems are 20/0, and weapons are all T4 flat phys with a 115% increased phys benchcraft, so nothing too nutty. Obviously you can find and use better weapons, but the point is to establish a rough floor for the builds. List DPS numbers are either on weapon alone or weapon + Heatshiver; no other items are equipped. Naturally, there is room for additional scaling based on crit or more added flat damage etcetc; I leave that to players more experienced in min-maxing melee builds than I am.

All builds use Wild Strike to substitute for Frozen Legion (other than the Slow Chieftain which uses Ice Crash, for reasons which will become obvious later). To account for EAD and cooldown, there are custom configs of 16% more Wild Strike damage (to bring its 231% EAD up to par with Frozen Legion's 270%), and a varying attack speed modifier to get its attack speed down to 0.6s. If you tinker with the builds, remember to adjust the attack speed modifier to match the CD cycle or you will get spurious results, since this is the one custom modifier that is not proportional.

For the Chieftains, a custom modifier of Gain 40% of Physical Damage as Extra Fire Damage is used to approximate the average effect of Ngamahu, Flame's Advance rather than to have it up all the time. Where curses are involved, there are also custom curse configs to approximate the new curse values (as well as the new % less effect of Hextouch, if applicable).

Disclaimer: Some of the Chieftain ideas may have been informed by an earlier post: https://www.reddit.com/r/PathOfExileBuilds/comments/zar6qk/frozen_legion_chieftain_league_starter_concept/.

Builds

1. Chieftain (normal): https://pobb.in/oGtVQQ7kwDAI This uses a regular physical axe and abuses double conversion - first to full cold via Ice Crash and Frozen Legion, then through Avatar of Fire + Cold to Fire to get an outsize damage boost from Hatred. You also get significant phys added as fire from Ngamahu, Flame's Advance, as well as minor boosts from the tree. Because all your damage is fire only, we can't use Heatshiver, but we still achieve a rather respectable 900k DPS (excluding Ignite damage) on a 2-mod rare weapon alone.
2. Inquisitor: https://pastebin.com/wDn7SRSP Arguably how GGG envisioned Frozen Legion should be played. Glacial Hammer is the main skill, assisted by Tribal Fury splash, its mastery's +1 strike, and Herald of Ice. We use Heatshiver to gain significant cold as added fire, since we have the guaranteed freezes from Glacial Hammer, and use Righteous Providence to obviate the need to expose. Since we're a crit build, Assassin's Mark is the curse of choice. This hits 800k DPS on a Judgment Staff and Heatshiver, could benefit from a lucky Hegemony's Era drop, and we pack some block as well.
3. Raider: https://pastebin.com/gJMtMb8p This uses Frost Blades for better clear and uses Frozen Legion to supplement single target; it shows when Frozen Legion deals almost as much damage as Frost Blades. It's a little weak to be honest, only hitting 500k DPS with Heatshiver on a T4+benchcraft axe, but a Debeon's Dirge (not a very rare weapon either) bumps its damage up to 800k DPS which is quite respectable. That said, it's not particularly impressive next to the Chieftain or Inquisitor which hit better numbers.
4. Chieftain (slow): https://pastebin.com/0TKetKBZ This is the meme/big brain version. If you attack so slowly, Frozen Legion becomes super attractive in having only a fixed cast time, so you might as well use it exclusively and spare yourself the pain of attacking. For this reason, it uses Ice Crash to simulate Frozen Legion, using custom mods to adjust Ice Crash's EAD to Frozen Legion's and modifying the attack time to hit 0.59s to be representative of your true DPS (because otherwise the attack rate is so slow, you hit harder than your DPS). It also abuses the same conversions as the normal Chieftain does, but this has many issues, namely what happens with super slow Legion attacks, as well as the possibility of super spiky damage since it relies a lot on chance to deal double and triple damage.
5. Bonus: https://pastebin.com/BwhFS5md This is the PoB I used to do the bulk of theorycrafting. The important one here is the Notes tab, which contains all of the working used to generate the numbers in this post, if it's of interest to anyone. It also shakes out the Frozen Legion numbers - assuming it doesn't scale with level, Frozen Legion looks like it'll be worse than the proposed 20/20 version by about half of the quoted damage numbers - i.e. not worth using at all. It also contains a number of build ideas that died, like trying to shove in Shockwave for a 3x4L setup (the damage conversion is a PITA), Martyr of Innocence for flat fire, strength stacking with Brutus', and a Hierophant Mind of the Council idea (I thought casting the spell only would bypass the penalty of MotC, but it might not work that way).

Conclusion

I hope those of us looking forward to being able to start a new skill can get some ideas from here. Also if you have any ideas on mid-endgame scaling, please do chip in as that is very much not my strong suit, and it would be nice to hear if Frozen Legion can scale competitively.