I agree with both Swiftblade and Angwil on this.  At first I came into this event thinking it was like the last one, which was painfully expensive to get any reward, but after playing around with it the champion training aspect of this one actually makes it significantly easier to get some of the items.

I think I saw some math and videos floating around, but it essentially boiled down to about 4k energy to get the leggo book or 5 star chicken, which is a price I'll easily pay.  It's even less if you use a bunch of XP Brews.

I have also essentially just built a bunch of food champions and walked away with simple rewards, so in that facet I actually quite liked this event.  It is much better than the artifact enhancement + dungeon divers combination from before

I bet you didnt summ how many energy needed to get the two highest rewards.Try to summ and see the forest from the tree.

The wizards at HellHades have already done the energy breakdown, and you can find the full video at https://www.youtube.com/watch?v=uzvjg4_VZAk if you are interested.  If you just want the results though, it is below

Assuming you are running brutal 12.3 to build food from 2 to 5 stars, you need 2,728 energy to get the Leggo book, and 2,968 energy for the 5 star chicken.  If you just want the Sacred shard, then it is 8,250 energy.  If you want to complete everything, then int is 13,888 energy.

Personally, I think the cost of energy for the leggo or 5 star chicken is cheap for this event, even if you were to get both.  

Note that this is technically using the optimal route and averages.  If you use XP Brews you can reduce the requirements 

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Why do I care about the two highest rewards? All I care about is getting a free lego book for just playing the game and not needing to do anything extra. Why would I complain about getting a free lego book?

Don't you dare try and make me play efficiently, Krama!

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If you dont care just the lego book, try to write to developers, you dont want sacred shards, delete them if you should get one.

Those two rewards what anyone triyng to reach mostly in the game. But, this event before personal reward pvp and fusion, where the important resources the energy or wont complete if dont have enough. 

I am enjoying Hero.  I will get the lego book, use 320 gems and 60 mystery shards.  But game rewards will have me about even on gems and 50 ahead on mystery shards when the game ends compared to when it began.  Its a free lego book for me.  

What i did was go for the middle tree first actually. I went to get the XP bonus (i had none left in stock). Cost me 2300 hero points. Then i went left straight to the lego book, but getting the chaos ore, not the blue book, i dont really need that one. I think i may have enough leftover to start the third branch to get the energy and maybe another small reward when all is done.

The lego book is essentially free from using the daily energy you accumulate and daily rewards.  

As stated earlier the only people complaining are those that see a sacred shard and think that is the prize they have to get... dumb

Free lego book events are always appreciated. Thank you plarium :)