Bloom of Twilight Revive the Land

The skill is designed to make barren land into fertile land. If the land is already fertile (a.k.a. purple) then the spell will have no effect. So you should only cast this spell on non-fertile land or barren land. If a tile is next to barren land, then it will possibly upgrade the food output of that tile if there is enough barren land nearby to change.

From your screenshots notice it only changed your barren landscape and made it purple. The purple landscape then allows better food and thus more settable sites show up.

Under the covers, all of the barren tile spots actually have food/materials/essence "points" assigned to them, but there is a threshold for them to appear (I believe the default is a combined total of 6 "points".)

Over time, as tiles are under your "dominion" (your faction outline on the map) they may increase their "points".  Not sure if this only applies to food, or if occasionally materials or essence will "upgrade" as well.  This is why sometimes you'll see new settleable spots appear inside your dominion; they reached the threshold to become visible. This effect applies to already settleable tiles too. There is a random factor in these upgrades, i.e. if you reload, it may or may not happen in any given turn transition.

What probably happened is that the "upgraded" tile, since it was in your domain, succeeded in its random chance to improve.  The fact that you cast the Bloom of Twilight nearby at the same time was a coincidence.

Note that the maximum "points" is 9, so once food + materials + essence = 9, it's done (unless you modded the game.)

Actually, that's not what his screenshots show. He did indeed upgrade a tile from 2/4/2 to 3/4/2 by casting the spell. I didn't realize this was possible. I also doubt this is worth doing a lot since the mana cost for the spell is so high... it will probably be better to cast 'bless city' more often instead.

danil, the way the spell works is it only affects the 'broken' land you can't settle on. If you cast it inside an area where the land has already been 'revived', it will have no effect. What happened in your example here, I believe, is that because you revived land next to tiles that were already revived, these revived tiles had their yields increased due to the broken tiles becoming active, ie. some sort of 'neighbour bonus'. So, because there is now less desert/broken land around that essence tile you are interested in the grain yield increased there (3 is the standard grain yield for plains tiles).

ok thanks for help people, i only wanted to know how this works to upgrade tiles in my prefered spots but i think by what you all are telling its 'neighbour bonus'(Apheirox) at least i know where it cant be done.

The Screenshots is from a place where all the tiles where barren even the ones in the screenshot 1, so i cast Bloom and the tiles become fertile then i saw a 2 essence one and upgraded its food to settle there.

Ow and i can make it outside my territory too.

Thanks for letting me know the maximum points its 9 (Crastiloowa) so ill not spend my time trying to improve a tile more than this.

It is done by casting the spell with the center of the radius far from the tile you want to improve but it need to revive some land in the same cast or it will not improve(neighbour bonus?).

Another example(Outside my territory) from a old save this time the count is 8(4/3/1) but i dont know if i can go further because i only have mana in this save for 2 spells, so i cant tell if i can go to 9(5/3/1).

3/3/1 now was nothing before(barren)  http://steamcommunity.com/sharedfiles/filedetails/?id=187949841

After 4/3/1 now  http://steamcommunity.com/sharedfiles/filedetails/?id=187949951