Editing Age of Sigmar/Tactics/Order/Idoneth Deepkin (section)

===From Battletome Idoneth Deepkin===
*'''Royal Council:''' (610pt. min.) [Battalion: 140pt.]
''Requires an Akhelian King (Or Volturnos), a Tidecaster, and a Soulscryer. ''

Adds a new Command Ability, if the Akhelian King is the general. You can add 3" move until next hero phase for 3 friendly Idoneth Deepkin within 12" of the Akhelian King. The Soulscryer and the Tidecaster have to be within 3" of the Akhelian King to use this. Effectively nerfs the Soulscryer's ability to outflank because he needs to be within 3" of the King to use the Ability of this Battalion (unless you take an extra Soulscryer via the Ionrach enclave). Either way, taking the King as general means you can't reverse the tides with the Tidecaster.

*'''Akhelian Corps:''' (830pt. min.) [Battalion: 100pt.]
''Requires a Akhelian Leviadon, 2-4 units of Akhelian guards and 1-2 units of Akhelian Allopexes''

You can reroll a hit, a wound, a save, a run or a charge roll for one unit of this battalion wholly within 12" of the big turtle per phase.

*'''Namarti Corps:''' (660pt. min.) [Battalion: 100pt.]
''Requires a Isharann Soulrender, 2-6 units of Namarti Thralls and 2-4 units of Namarti Reavers''

The Soulrender resurrects 3 models instead of D3 with his Lurelight ability.

*'''Alliance of Wood and Sea:''' (1410pt. min.) [Battalion: 140pt.]
''Requires (deep breath....) a Isharann Tidecaster, 2 units of Akhelian guards,  a unit of Akhelian Allopexes, a unit of Namarti Thralls, a unit of Namarti Reavers, and some Sylvaneth - a branchwych, 2 units of Dryads and a Treelord Ancient''

The Sylvaneth in the Battalion benefit from Emissary of the Deep Places regardless of your chosen Enclave. 

Essentially a full Start collecting box of Sylvaneth, plus 4 more dyads. Also smart to buy one Awakened Wyldwood since the Treelord Ancient's ability Silent Communion gives you one per battle despite your Sylvaneth otherwise not having access to tree generation. Ideal for an existing Sylvaneth players wanting to ''branch'' out to something new (pun intended). But does it work as an useful army?

Other useful considerations would be that the two Sylvaneth Wizards in the Battalion don't have access to non-Warscroll spells, and especially considering that the one spell on the Treelord Ancient's scroll depends on Awakened Wildwoods to be useful, it's probably wise to take at least one Sylvaneth Endless Spell (or generic one for that matter) to give them something to do. Furthermore, Dryads are one of those units that doesn't perform well at their MSU size of 10 (getting a +1 to Save for 10+ models), so you should go ahead and plan on at least two units of 20 models (if not 30). Additionally, the added artefact you'll be getting from this Battalion will be wasted if you don't take at least one additional Idoneth Hero (since these Sylvaneth still count as Allies for the purposes of doling out artefacts). Finally, since the Allied Dryads don't actually count as Battleline (despite what Azyr says), you'll either need another unit of Namarti (if you take the Tidecaster as your general), or one of the Akhelian Kings (to make the Eels Battleline). Essentially, the Battalion is more for flavor, as it's super limiting of what you can actually end of taking in a 2000 pt army, but it could still be fun (especially if they update the Sylvaneth scrolls). 

You could add two units of Kurnoth Hunters as allies (given anyone playing this will most likely have some lying around), but they wouldn't get the Tides Of Death (unless you went Ionrach).