Even if you decide not to build the 2nd I wouldnt empower the 1st until youre lucky / unlucky enough to pull a 3rd.  +1 gives minimal gains while at least +2 gets you a speed boost. 

3v3 Arena is Tag Arena?

Siege I tried to play, I put 2 teams on the deck, but I was blocked further by the lack of Siege resources, so nobody called me in fighting action. I even don't know how to play. This mode of playing is either nonfunctional, or not intuitive to play, without studying it in tutorials.

Both Krixia are already fully booked.

Yes, 3v3 is Tag.  

Well, if you booked the 2nd Krixia, then you might as well finish building her. The books are by far the scarcest resource in building a Mythical.  

Why the H would you book a toon you were thinking about using for empowerment?

I was thingking to use both of them in Hydra, in a Trunda tier, instead of Yumeko (2 Copies), recomended here: Hydra Clan Boss: Top 20 Champions 

Unfortunately Krixias will not work the same way.  They do not reset each other's cooldowns the way Yumekos do. 

Unfortunately Krixias will not work the same way.  They do not reset each other's cooldowns the way Yumekos do. 

Yes, I have noticed, but I hoped to keep 1 in alternate form, to decrease the cooldown of the team, and other in base form to increase  the cooldown of Hydra.

Is it possible to increase the cooldown of Hydra?

A few months ago, in a move of totally predictable idiocy, Plarium preserved Yumeko's ability to reset other copies of herself and snuck new language into the skill description of every other reset skill explicilty stating that it cannot be reset or have its cooldown reduced.

If any toon should be able to do that, you'd think it would only be the Mythical, but nope, still just the Void Lego. 

But then, is it possible to make 2nd Krixia with a delay so to redecrease the cooldown of Trunda later, so to be albe to have almost the same function as 2 Yumekos do? 

Yes. Using the Team Preset function, you can stagger either/both the transiiton to Alt Form and the usage of the Alt Form A3, which can let you reset Trunda two turns in a row right throughout the fight, but each Krixia will be on a 5 turn cycle and their resets will overlap with Trunda's natural resets.  

Since Yumeko reduces CDs by 3 turns (versus resets)on other copies of herself, the ability for 2X Yumeko to reset Trunda is essentially on a 2 turn CD.

So, you sugest to use Krixia in another Hydra team, and free the slot of Trunda Tier for another champion?

Or you sugest to not use Krixia at all, in Hydra battles, or Trunda tier?

PS Yumeko is hard to obtain even 1 (so, 2 is almost impossible) and it does not deserve to spend money on void shards, instead primal shards...

That depends on the rest of your Roster and the quality of your Trunda Build.  Give it a try and see what you get for Damage.  A strong Trunda team is still a very good Hydra Comp.  

I don't have a Trunda or a Yumeko. I do have a Krixia. I use her extensivley in PVP, but have never used her in Hydra.

For Hydra, I use a Titus Comp, a Kro'Kad Comp and a Thor Comp.      

A few months ago, in a move of totally predictable idiocy, Plarium preserved Yumeko's ability to reset other copies of herself and snuck new language into the skill description of every other reset skill explicilty stating that it cannot be reset or have its cooldown reduced.

If any toon should be able to do that, you'd think it would only be the Mythical, but nope, still just the Void Lego. 

Its also super inconsistent.  Like Pain Keeper + Emic can reduce cooldowns of each other still too, and I think Donnie can for some champs as well.  

I believe that Emic can have his A2 CD reduced/reset by anyone.  I think that skill is the only CD reduction skill that has no qualifiying verbiage one way or the other.

I had forgotten about PainKeeper getting the 1 Turn Reduction language, which means that Donnie & Lix could reduce her CD as well.

IMO, Kymar is the one that really got the short straw when they added the new verbiage. He is a lego with a 6 turn CD on his Reset skill.  When they updated his language, they could have at least dropped it to 5.