The Summoner Specialization is an extension of blood magic that summons demons from the Fade to fight with your party.  All abilities are cast with health rather than mana, regardless of whether or not Blood Magic is active.  (Note:  Improved Blood Magic items will lower the health cost of all Summoner spells, but not in the exact way they affect normal Blood Magic.  I tried to get it fairly close, but it's not quite the same.)

All Summons are Active abilities rather than Sustained.  I did this for a couple of reasons, but mostly because I don't quite trust my method of keeping them around in Sustained mode (a la my Summon Wolf Ability).  Also, I can suspend disbelief for a lot of things in this game, but Hawke running around Kirkwall with a literal demon permanently trailing after them might just break it. (And speaking of, yes, a lot of your companions would DEFINITELY disapprove of ... most of these spells.  Does it really make much sense for Hawke to be summoning demons while also hunting down blood mages who summon demons?  Well, I don't know, maybe Hawke's a hypocrite.  Just go with it.)

All Summons are cast as placed AOE spells, rather than summoning directly by the caster.  This is because it sometimes takes them a little bit to get moving, and if you're not in the middle of the action, it may delay them.  If you're giving the spec/spells to a companion rather than Hawke, you'll want to set up their tactics to target an enemy ("Nearest Visible" for example) and activate the ability.

Blood Pact
The modal ability that must be active in order to cast any of the summon spells.  Blood Pact provides a bonus to magical power and blood magic cost, but adds a small penalty to combat health regeneration.

Summon Desire Demon
As it says, summons a Desire Demon.  When upgraded, your Desire Demon will gain Enlist, an ability to (occasionally) Charm or Possess a nearby foe.   So if you see someone on the battlefield suddenly change allegiances or transform into an abomination, don't be alarmed, your spec isn't broken.  That's just your Desire Demon doing its thing.

Acquiring the ability gives you a small permanently penalty to health.  (Don't worry, it's small, like -2.)  This is for lore reasons -- you're meant to be entering into a pact with a demon; there needs to be a cost.

Summon Rage Demon
Summons a Rage Demon to fight with you.  When upgraded, your Rage Demon gains Combust, an AOE fire ability to take out nearby foes.

The penalty for acquiring this ability is a small permanent decrease in defense.

Summon Shade
Summons a Shade.  When upgraded, it summons TWO Shades!  They don't gain extra abilities, because instead you get two of them.

The penalty for acquiring this ability is a small permanent decrease in magic.

Animate Dead
Technically this was a Spirit spell in DAO, but DA2 seems to consider it blood magic, so here we are.  That said, it works similarly to the spell in DAO.  Target a group of dead enemies and you can turn one into a Corpse to fight with you.  When upgraded, you can animate two skeletons.  If you have the "Advanced Reanimation" property (see the new item properties below), you can raise an additional skeleton, for a total of three.

If the spell fails, you will not lose any health and it won't go on cooldown.

Possess
This one is very mean.  You probably shouldn't do it.  That said:  Possess allows you to use blood magic to turn an enemy into an Abomination that will fight with you for a time, a la Uldred.  There are a couple of restrictions to this:  only humans, elves, and qunari can be possessed; enemies that are Rank 2 or higher cannot be at full health; and unless you have "Forbidden Knowledge," you can only Possess mages.  (I was going off the lore that normally only mages can become abominations, but Tarohne and her followers were able to possess Templar recruits and others.  That's why the Forbidden Knowledge ability is linked to her.)

Note on using Possess:  If you want to loot an enemy you Possessed, you'll need to wait until after their created abomination dies to collect the items.  Also, this spell should be set up so that you can't Possess anyone really important, but just to be on the safe side, use it with caution, okay?

If the spell fails, you will not lose any health and it won't go on cooldown.

Blood Oath
Passive ability that boosts all your summons.

Consume Spirit
This is a special ability that you can only acquire by equipping a special item, the "Tevinter Bloodstone," which can be purchased from Magnus's Wares on the Wounded Coast in Act 2.  Once you have the item equipped, you can find the ability on your Abilities page and add it to your hotbar.  Consume Spirit is an activated ability that drains health from active summons in order to heal the caster.

The Fade Weaver specialization is an extension of Spirit Magic.  Because of this, it requires you to have at least one ability point in the Spirit school of magic.  Because I understand that's annoying, I've provided a couple of potions for you to use if you don't normally use the Spirit tree.

Please note that Fade Weaver is not meant to be used in conjunction with the Summoner spec or Blood Magic.  Spell Wisp will disable both the Blood Magic and Blood Pact modals, and Mana Clash cannot be cast if Blood Magic (or Merrill's version of it) is active.

This spec basically got made because I discovered you can migrate VFX over from DAO pretty much wholesale, and then I needed abilities to use them on.  So here you go.

Spell Wisp
Modal ability somewhat similar to the spell in DAO.  It provides bonuses to Magic and Spirit Damage for an upkeep of 10% of mana.  Spell Surge and Manafont require Spell Wisp to be active.

Fade Walk
A teleport spell.  Place your targeting AOE where you want to go, and presto, there you are!  Fade Walk has two upgrades:  one that damages and knocks back nearby enemies when you reappear, and one that restores mana in proportion to distance traveled.

Note:  depending on how far you travel, there may be a slight lag in your game when you reappear.  This hasn't stopped me from using it to teleport all over the place, but your mileage may vary.

Mana Clash
Although this shares a name with a DAO spell, they don't do quite the same thing.  That's because enemies in DA2 do not have mana.  At all.  So instead of basing damage off of a mage's mana, it's based off the caster's.   Mana Clash consumes half your current mana and deals damage dependent upon how much mana was expended.  Also, since -- in spite of what the Templars want you to think -- there really aren't that many enemy mages in the game, Mana Clash will still do damage to non-mage enemies, just to a smaller degree.

When upgraded, the damage increases, and it also dispels and silences enemies.

Spirit Dance
AOE field that damages enemies, restores health to allies, and provides small bonuses to Magic/Spirit Damage/Spirit Resistance.  "This looks like Spellbloom!" you say.  Well, that's because it is.

Spell Surge
An ability that resets the cooldowns of all of your abilities (except its own).  This ability shares a cooldown with Manafont until they are both upgraded.  Spell Wisp must be active to use it.  When upgraded, it also delays the cooldowns of nearby enemies.

Manafont
I wanted an ability that let you cast spells freely for a short time.  Since I couldn't crack that, you get this instead:  a supercharge to combat mana regeneration, so you can effectively  cast spells freely.  When upgraded, it will also boost the mana regeneration of nearby allies.

Conjure Wolf
A "summoning" spell for the Fade Weaver, this operates similarly to all the summons in the Summoner specialization, calling a Spirit Wolf to fight alongside the party.

For some reason, adding new specs wasn't enough for me, and I decided I wanted to create new accessories with new properties that interact and alter those new spells.  So this is what you get.  I've added several new properties (and items that have them) to work with your new specializations.  They are as follows:

Summon duration +5 seconds
This one is pretty self-explanatory.  Items that have this property add to the duration of all summons (including Conjure Wolf).  Because you can stack these, it does mean you'll potentially get to the point where duration of your summons is greater than their cooldown, so you can build yourself a little demon army.  It's not like Kirkwall has any other problems.

I added accessories with this property to several prominent blood mages in the game, so you can pillage their corpses and add to your powers.  "Apostate" and "Demonic" accessory loot items may also randomly gain this property.

Advanced Reanimation
This property is only on a specific item, the Blood-Fused Crest, which drops off Decimus during Act of Mercy.  If you miss picking it up there, I also added a copy of it to the Nexus Golem's Wares in Sundermount in Act 2.

Advanced Reanimation allows you to animate one additional corpse, bringing your potential corpse count up to three, and once again adding to your demon army.  Congrats.

Forbidden Knowledge
Forbidden Knowledge is required to Possess non-mages, and it can be acquired in three ways:

In Act 1, the Canticle of Eskrella, a unique belt accessory, drops from Tarohne during Enemies Among Us.  You will gain Forbidden Knowledge and be able to Possess non-mages as long as the Canticle is equipped.

In Act 2, the "Book of Forbidden Lore" that you can receive during the Forbidden Knowledge quest can now be used as a consumable to gain the Forbidden Knowledge ability permanently. (Note: I altered the vanilla file for this item, so this is the one potential incompatibility this mod will have.  I don't think any other mods change it, however.)  You will only receive the Book of Forbidden Lore if you read one of the books or accept the book's deal.  If you destroy all of the books, you can't get it in Act 2. (That's also definitely why I just made my Forbidden Knowledge Quest Fix.)

In Act 3, if all else fails, I dropped a copy of both the book and the Canticle in the Nexus Golem's Wares in Sundermount.

(Note:  if you acquired Forbidden Knowledge permanently via the Book, it should not be erased by using a Maker's Sigh, but if it does, you can add it back manually by using the console and typing: runscript addtalent 292091.)

Improved Mana Clash
Items with this property add +25% of mana expended to the damage of Mana Clash.  Since these stack, it could potentially make it way too powerful, so they may need to be rebalanced.

A few special items with this property will either drop off mage enemies or be given as a reward.  "Circle Mage" accessory items may also randomly gain this property.

Dance of the Elements
Dance of the Elements alters the damage, visuals, and bonuses provided by Spirit Dance to be dependent upon the damage type of the mainhand weapon you currently have equipped.  (For example, if you have the Hypnotist's Staff equipped, Spirit Dance will be Electricity based.)  If your mainhand weapon is Physical Damage based, this property is useless, as Spirit Dance will not be altered.

Fade-Touched
The Fade-Touched property alters Fade Walk.  Fade Walk finishes the cooldown of Mana Clash and may trigger a Spell Surge, and for ten seconds your next Mana Clash is free of charge.

This can be fun, but can also get you into a lot of trouble, because as it turns out, teleporting into a bunch of people, knocking them over, and then Mana Clashing them kind of makes them mad.  Use at your own risk!

I added four items with this property into the game.  The first, the Tapestry Stone, can be looted off a pile of bones in the hidden cave during Wayward Son.  For the second, I changed the "Tome of the Slumbering Elders" that you may receive from Marethari into an equippable accessory.  (Note:  If you're using Quest Rewards Fixes, you'll need to remove the Marethari portion of that so that she'll still give you the Tome.  I altered the reward for her to also give the attributes item provided by Quest Rewards Fixes.)  Additionally, I put two items (The Horned Knight's Wedding Sash and the Ring of the Masked Andraste) in the Nexus Golem's Wares, one in Act 2 and one in Act 3.

Bewitched
The Bewitched item property alters the bonuses of the item itself.  Bewitched items are restricted to mages and change their properties dependent upon the damage type of your mainhand weapon.  For instance, a mage equipped with a cold-based staff will receive a bonus to cold damage from a Bewitched item.

Note:  I also discovered Rune Slots can be placed on Accessories (who knew?  not me!) -- so I added rune slots to some of these.  If you're going to add a rune to a Bewitched item, make certain it is not a rune that boosts damage type.  Otherwise, that bonus will be removed along with the original bonus if you switch mainhand weapons.