Fall of Ashira

Heya, I'm IronCrusher, a new cardsmith who has been quite enjoying making cards, the cards i've been making are part of a set: Fall of Ashira, this set is part of a 3 part block i plan to create. (P.S. this block does not follow anything related to normal MTG story) (P.S.S. I already have a story in mind for the rest of the block.)

Story: Danam, King of Ashira searched audience with a mysterious being known as "The Emperor", the haughty king managed to severely anger this being, the being send him out with a promise to destroy his Kingdom.
Enraged, The Emperor made a deal with a powerful being, salvation in exchange for destruction.
Destruction followed, the plains of Ashira trampled by demons, grounds covered in ooze, life sucked out of everything, many innocent fled the onslaught that had ocurred, only few able to fight back. The demons didn't stop, slowly trampling the forests surrounding Ashira. Azura, The Mad Faerie, decided to make use of the chaos to rally her troops and siege control of the planes of Ashira, Myria, Faerie of Peace could only lament as her breathren were about to make a horrid mistake. The Kingdom of Geasha was under a lot of pressure, one side, demons, other side, maddened faeries. When Madeo, lord of the forest saw the innocent, he prayed as the angels came to his aide.
Demons trampling the planes.
Faeries waging war.
Survivors running and hiding.
Knights, warriors and soldiers fighting to protect.
Oozes seeping through the corpses.

This is about the basic of this set.

Mechanics i created in this set:
Remorse - When ... leaves the battlefield, if it was dealt combat damage by a creature, put X -1/-1 counters on that creature, where X is equal to ... toughness. Otherwise, that sources controller loses life equal to ... toughness.

Devourer N (This creature can take any N power, thoughness or other abilities from a creature it is blocking or is being blocked by, this is done before the damage step)

Example Commons:
https://mtgcardsmith.com/view/fearful-child-2?list=set&set=31927
https://mtgcardsmith.com/view/flee-2?list=set&set=31927
https://mtgcardsmith.com/view/sole-witness?list=set&set=31927

Example Uncommons:
https://mtgcardsmith.com/view/emperors-rogue?list=set&set=31927
https://mtgcardsmith.com/view/last-stand-28?list=set&set=31927
https://mtgcardsmith.com/view/erina-brave-child-1?list=set&set=31927

Example Rares:
https://mtgcardsmith.com/view/klay-mistreated-genius?list=set&set=31927
https://mtgcardsmith.com/view/blade-of-geasha-1?list=set&set=31927
https://mtgcardsmith.com/view/hunting-demon?list=set&set=31927

Example Mythics:
https://mtgcardsmith.com/view/geotrait-angel-of-protection?list=set&set=31927
https://mtgcardsmith.com/view/onslaught-of-the-fairies?list=set&set=31927
https://mtgcardsmith.com/view/rena-the-emperor?list=set&set=31927
https://mtgcardsmith.com/view/rena-devourer-of-empires-1?list=set&set=31927

The set is far from done, but you can find everything i've done here: https://mtgcardsmith.com/user/IronCrusher/sets/31927

I'm personally quite unsure if the way i'm building this is decent so if anyone has any critisism, suggestions, thoughts, questions and/or advice for me that would be greatly appreciated!