Me too, @Trajector. I can hardly wait!
All in all, this expansion looks really nifty! : D
About Incarna, the funny thing is, I had an idea for a practically identical mechanic. Great minds think alike! (That, or GTG is stealing my ideas!)
Seriously, though, it looks really cool, having a single token on the island that you can move around and do stuff with. And it is obviously what was meant before by “facing the Invaders head-on.”
Okay, here is what I was able to glean from the campaign page and video:
Spirits:
-
Incarna Spirits:
- Ember-Eyed Behemoth, “a massive titan that destroys everything in its path.”
- Towering Roots of the Jungle, “a mighty tree that defends the land and quiets all conflict around it.” Vitality confirmed! (It’s mentioned on the Spirit’s panel in the video.)
- Breath of Darkness Down Your Spine, “a shadowy figure that slinks through the darkness and sends lone Invaders to the Void.” Could this Void a reference to Sentinel Comics’ Void in the same way that Sentinels of the Multiverse’s Nexus of the Void environment is a reference to Spirit Island‽
- 1 Other Spirit, that looks like some sort of floating sun-head.
-
Non-Incarna Spirits:
- Hearth Vigil. The short name makes sense for a Spirit that is close to the Dahan, as Thunderspeaker is. Also, the name sounds strangely familiar; has it been mentioned in lore before?
- Roiling Waters. It looks like this Spirit gets some special cards that aren’t Powers‽ It’s possible that “Roiling Waters” is just the name of those cards and not the Spirit. And it appears that this Spirit will get its own tokens.
- 1 Other Spirit, one that “carv[es] swathes of overwhelming destruction.”
- 1 Other Spirit, “a Spirit who starts the game dying and must find their way to a new form.” That description reminds me of Voice of the Deepest Gorge, who was mentioned in the lore section of the core game’s rulebook. Could this be that?
It looks like there are three types of new special tokens, but they don’t look like the same type of tokens as 
etc. Towering Roots of the Jungle uses the green ones (Vitality), and I think Roiling Waters uses the blue ones. However, it’s unclear wether these tokens will each be exclusive to a single Spirit, or (like the B&C and JE tokens) be used by several Spirits, Power Cards, and Aspects.
It also looks like we’ll be getting at least one Aspect for Heart of the Wildfire and a Scenario entitled “Destiny Unfolds.”
If Vitality ends up not being exclusive to Towering Roots, I think it would make a good fit for the Wildfire Aspect.
There’s only four Incarna Spirits, yet there are six Incarna tokens. However, taking into account the info I found above, I speculate that there will be one Major Power and one Aspect that can each grant just any old Spirit an Incarna.
And it appears that, in addition to counting as 
, one of the Incarna will count as and two as 
.