i would consider adding 2 Lightning Greaves in here. you have 19 creature cards total that would benefit tremendously in this deck from it.

• it only costs 2 and the equip is 0, so it is perfect for the tapping of mana-elf dorks

Here's a quick play test i did pretending the Coat of Arms were Lightning Greaves (just because you have 2 of them in the deck):

1. Draw, Land, Elvish Mystic

2. Draw, Land, Lightning Greaves , Llanowar Elves , Llanowar Elves

3. Draw, Land, Elvish Archdruid , Elvish Archdruid , Joraga Warcaller kicked 4 times, comes in as a 5/5 and everything else has +4+4 from him.

4. Draw, NO Land, Immaculate Magistrate , tap for 7 +1/+1s on Joraga Warcaller , swing in with FIVE 14/14s.

That's the power of Lightning Greaves

AND, if you play 4 Nykthos, Shrine to Nyx , you could have a lot more mana for Emrakul, the Aeons Torn early.

CurdBrosBrewingCo can back me up here.

Dreno33 is 100% right about Lightning Greaves . It completely changed my deck Elf Devotion (Modern).... And I only run two of them. This is especially true since you're running the Elvish Archdruid / Umbral Mantle combo. Elvish Archdruid + Lightning Greaves is always a good idea :). Winning a turn earlier is a godsend in Modern.

Slate of Ancestry is a really cool idea! Especially in Elf decks. It becomes quite a bit worse in matches with heavy removal/control; but it is an extremely good fit in a deck that pours out its creatures fast and only holds on to a card or two in hand....Queima presented me with the idea of Umbral Mantle ...so I know he knows his stuff too :)

Great deck!

How does it look now?

With the Elvish Archdruid / Umbral Mantle Combo, I'm surprised with all the mana dorks instead of token producers like Elvish Promenade Take a look at Doubly Privileged Genesis Elves

Personally I like the Joraga Warcaller Immaculate Magistrate combo but yeah there are some downsides to it. With bigger cards like your eldrazi you may want Elvish Piper . I'm also a fan of Lys Alana Huntmaster you may find it a bit slow and it doesn't seem your going the token route. Khalni Hydra is good in any mono green especially elves. But, anyway good deck. +1.

You should probably put in Collected Company. It digs through your deck, finds the creatures that you need, and puts them right onto the battlefield, all for 4 mana at instant speed.

Why are you sideboarding Torpor Orb and Emrakul? This seems like a good deck but check out http://tappedout.net/mtg-decks/22-11-15-uil-elves/ if you want any suggestions. Also, consider [card]Myr Superion[/card]. It is a very good card, especially in elf decks and CoCo decks.

Not the worst deck. but not really elves if you wanna do Eldrazi in sideboard. Also I have to admit I live the addition of Craterhoof Behemoth but if want a strictly elf modern deck check out my deck. :) :) :)

http://tappedout.net/mtg-decks/elf-trample-4/