doctorhydrogen

People generally drop the commander in the side-board.

I've been running landfall for awhile, first with Xenagos because there wasn't really good RG option, then Omanth, now Mina and Denn. Mina and Denn works best imo. Omanath actually is a better deck if you build him as elemental tribal, but it's not a lot of fun and kind of on rails and doesn't do much cool landfall stuff. This kind of build here lets you do crazy things with obscure cards which is way more fun.

Couple of things:

You need more draw. Yeah, the spells to get extra landfall proccs is great, but playing the extras from Mina and Denn is much more consistent. Harmonize is great, and I've had some blow-out draws with Momentous Fall. MF is nice because it's instant, and you can cast it in response to someone trying to destroy your incoming Baloth Woodcrasher that's jacked up to 16/16 or whatever. Greater Good works well for the same reason.

I'd replace Nature's Claim with Deglamer or Unravel the Aether. The life gain there is incidental, and Claim doesn't deal with Theros Gods, Blighsteel Colossus, Darksteel whatever, and Unravel/Deglamer get around graveyard triggers. Plus stuff is almost always harder to get back off a tuck than it is from the graveyard.

Valakut the Molten Pinnacle is great here. It's super easy to hit 5 mountains, and it turns landfall into removal.

I'd be cautious with Animist's Awakening. The problem I had was that often times when I cast it I had often times filtered out so many lands from my deck it didn't hit much.

If you can find one Skyshroud Claim is better than Explosive Vegetation since the lands come into play untapped. Plus you can grab Cinder Glade or Stomping Ground (or Tiaga if you get one) with it.

Omanath or Mina and Denn for the commander?

Whoops, yep, meant Outpost Siege.

Generally speaking you want cards that do lots of things vs. cards with narrow uses. For example

- Replace Naturalize with Deglamer or Unravel the Aether. They deal with Theros gods, Darksteel Plate, Blightsteel Colossos, stuff protected by Avacyn, they get around graveyard triggers, and stuff is almost always harder to get back from the library than the graveyard.

- Replace Ancient Grudge with maybe Hull Breach or Decimate or just either whichever of Unravel or Deglamer you don't use in the Naturalize slot. Flashback doesn't offset Grudge being so narrow.

- If you want a Fog effect replace Fog with Constant Mists. One extra mana to potentially re-use it half a dozen times is well worth it.

- For the same mana cost as Cleaver Riot you could drop Berserker's Onslaught and have it stick around multiple turns hopefully.

Don't like blue? War's Toll forces the counterspell player to choose between leaving all their mana free or doing nothing on their turn, same for Mana Web.

You need more draw. Citadel Siege is decent, as is Soul's Majesty, Hunter's Insight and Hunter's Prowess.

42 is too many lands in a mono deck with no draw and a reasonably low curve. You'll get flooded. 38 is plenty, and in that 38 probably should be Buried Ruin and Inventor's Fair

Mind's Eye and Staff of Nin are must-runs in mono-white IMO. You desperately need the draw, and both are relatively inexpensive. If you have the budget Land Tax and Scroll Rack are fantastic too as both are really good apart but make a great draw engine together.

Ah, thought you meant Aurelia as commander.

Angelic Accord makes a dude that you can fling to make a dude that you can fling, etc.

You'll need more draw. Outpost Siege, Mind's Eye and Staff of Nin are a start.

Council's Judgement does everything Oblivion Ring does but better.

It's not cheap but Scroll Rack is pretty amazing with Land Tax.

Thing is though Aurelia is an entirely different deck. Like you'd keep the lands and not much else. Most boros generals are so boring and similar you can just flip between them mindlessly, but Brion is one you can't.

This deck feels made for Rise of the Dark Realms.

IMO the extra mana and life loss on Anguished Unmaking is well worth the flexibility of dealing with anything over Unmake. Either that or go the other way and run Path to Exile. It's not that Unmake isn't a decent card, it's that there's just too many cards that are a little bit better

Brion is super fun, but he's a whole different deck so I never suggested it. It's not like swappping out Isperia for Medomi in sphinx tribal where not much changes; like 90% of the non-lands would change moving to Brion.

He's fun for sure though.

There's almost no way you ever hit the Urza's lands together. If you want a big mana option on a land you can probably support Nykthos,.

There's a like ten three-drop artifacts that are better than Manalith (Chromatic Lantern, Commander's Sphere, Boros Keyrune, Boros Signet off the top of my head).

Boros draw is so terrible. I'd run Staff of Nin, Outpost Siege and Mind's Eye for sure.

You could probably run Dispatch as a removal spell.

For one more mana than Inspired Charge you can cast Dictate of Heliod which also is instant speed, and gives your guys +2/+2 instead of +2/+1, and it stays on the field.

Buried Ruin and Inventor's Fair would both work nicely in this deck.

40 lands seems heavy for a mono colored deck that isn't doing goofy landfall stuff. Plus you're in green. I'd pull two to drop to 38 and maybe run Nature's Lore and Rampant Growth in those slots.

It's probably rarely going to matter, but Regrowth costs the same to cast as Revive and is relatively cheap to pick up, and it'll let you also get back Nykthos if someone Strip Mines it or an artifact that gets blown up. I mean, it's going to matter like 1% of the time so I wouldn't go way out of my way to get one but if you have one sitting around it's probably worth the change.

IMO ditch all those artifacts and just go full-on enchantress. Most of them aren't that good anyway; it's not like you're running five swords, etc. Then stuff like Verduran Enchantress, Mesa Enchantress, Eidolon of Blossoms turn into gross draw engines. Plus you get to then run artifact hate and just shut down some other decks.

Ground sweepers are also nice. Earthquake, Fault Line, Magmaquake, etc. all deal X damage to creatures without flying, which just so happens to be almost none of your dudes. Mudslide keeps non-fliers from untapping, which again happens to be almost none of your guys.

A note before I begin: Kaalia is kind of the running meme at the store where I play. Whenever someone loses they threaten "next week I'm gonna bring my Kaalia deck!" or something, because about once a month some new guy rolls in with his Kaalia deck that wrecks face at the kitchen table, sits down talking about how amazing it is, and proceeds to get steamrolled by any semi-competent player. It's our go-to reference for a commander that really isn't any good but seems amazing to new players.

That said, it's not that Kaalia can't be built well; it's just that she almost never is, and her weaknesses are super easy to exploit, namely that once she's off the table (or better, pinned to it being worthless with a Darksteel Mutation or Song of the Dryads or something) then you're just stuck sitting there hoping the Pokestops are close enough to spin on your phone while you wait to spend your entire turn hardcasting one big-ass dragon.

Ways to fix this:

MOAR PROTECTION: You've got Greaves and Boots, which is a good start. Next I'd go with Righteous War. 90% of removal spells in EDH are black or white, which means Kaalia will become immune to 90% of removal spells, and as a bonus it then makes a bunch of your fatties harder to remove and block. I'd also find room for Whispersilk Cloak and Champion's Helm.

MOAR DRAW: It's super easy to empty your hand in Kaalia, and you need to refill it. Necro and Phy Arena are good starts and you have tutors to fetch them, and a couple of your dudes draw. I'd also slot in a handful of sorcery speed raws, stuff like Ambition's Cost and Ancient Craving.

MOAR RAMP: More artifact ramp. It will make casting fatties easier, and make recasting Kaalia for the 14th time easier.

I personally would run Phyrexian Arena over Underworld Connections. Sure, you don't get the card right away, but it also doesn't suck up a land slot and doesn't make a tempting 2-for-1 target.

Hero's Downfall is strictly better than Murder.

Docent of Perfection has been a pimp in my Talrand deck. Since Talrand is a wizard he's super easy to flip, and then you double the tokens you make off spells you're already casting, plus he then gives Talrand flying.

Cast through Time is pretty gross here.

With a handful of drakes out Gravitational Shift becomes a win-con, and it can gut most other aggro or token decks.

If you want to guarantee you can cast it infinitely you could swap Lure of Prey for something like Defense of the Heart.

Lurking Predators and/or Wild Pair would also do great work in a deck this creature heavy.

Primal Surge would be fun to cast at least once in this deck.

For one more mana there's a lot more upside on Sylvan Library over Mirri's Guile. I've never wished my Sylvan Library was a Guile so I could play it one turn earlier, but there's been a gazillion times I was staring at three dudes and needed to get to a land or something and been saved because Library let me pay the life to draw and see three fresh cards next turn.

I'm not sure I'd go out of my way to get one or anything, but since you already have a Green Sun's Zenith, Dryad Arbor might be worth running. Turn one GSZ for zero to ramp Arbor into play is a pretty solid move.

I'd run Chaos Warp over Magma Jet all day. It deals with any problem permanent. It's the most underrated removal spell in the game.

Swap your Wasteland out for a Strip Mine. Strip Mine is strictly better and costs about $50 less.

Valakut the Molten Pinnacle? You're got a 13 mountains here and probably hit five pretty regularly. There's not a ton of downside, though it does ETB tapped.

You're at 12 instants/sorceries. You could cut a couple and pretty consistently drop 30+ cards on Primal Surge cast. Even without making changes though you could get some really gross Genesis Wave casts.

Prime Time is banned, so is Sylvan Primordial.