I think the're the colors of the book titles.
You have inside information. That's cheating
I personally think they should have a new CCG based around them. First Thomas Hunter should be...blue. Like Genesis. I'll make some up as well.
A Circle CCG would be awesome, but four books (more if you include the Lost Books, Paradise novels, etc.) might not have enough material for a whole new CCG. Not saying it wouldn't, but there might be a strech.
Here were some of the other ideas I had but haven't actually made cards.
Raison Vaccine/Raison Strain
1/1 Green enhancement/3/2 black enhancement
Heal any hero in play. Place on a hero.
Hero is immune to diseases After 2 turns, decrease
for remainder of game. that hero 3/3 per turn.
When hero reaches */0,
discard hero.
Michal
6/4 Silver hero
May band to Green or White Thomas Hunter or Gabil. Gains 2/2 against Shataiki.
Identifiers: Roush
Gabil
8/4 Silver hero
Hero is immune to Shataiki. May band to Green or White Thomas Hunter or Mikil.
Identifiers: Roush
Shataiki
3/2 Panic Demons.
Alucard
7/5 orange EC
Negate all special abilities on all good cards. Shataiki banding cannot be negated.
Identifiers: Shataiki
Black Powder Bomb
Artifact
If Evil Characters in battle outnumber heroes 2:1 or greater, you may discard this card to discard two Evil Characters.
Horde warrior
5/3 Gold Evil character Warrior Class
May band to a Horde Evil Character.
Identifiers: Horde
Horde Brute
10/9 Gold Evil Character Warrior Class
Negate all special abilities on non-weapon class characters and enhancements (except this ability). Battle is determined by the numbers.
Identifiers: Horde
Scabbing Disease
Gold Evil Enhancement
Place on a hero. Decrease hero 2/2 each turn. when hero reaches */0, convert that hero to a gold Evil character with abilities 3/3 less than original hero.
Falling Asleep
Green/Red/White enhancement
You may exchange a Thomas Hunter in battle with a Thomas Hunter in hand(, deck) or territory. Enhancements already played stay in battle.
(Can't decide if deck makes it too powerful)
Monique de Raison
5/4 (Purple or White) Hero
Search deck for a Raison Vaccine and add to hand to draw two. Cannot be interrupted.
Justin
9/5 Red/White hero Warrior Class
May choose a Forest Dweller to convert to an evil brigade of your choice and block rescue attempt. If rescue attempt fails, search an opponent's deck for a Lost Soul and put in play. Cannot be negated.
Identifiers: Forest Dweller
Qurong
9/8 Gold Evil Character Warrior Class
Search deck or discard pile for a Horde evil Character to make discard abilities on Evil enhancements cannot be interrupted.
Identifiers: Horde
Chelise
5/4 Gold Evil Character.
If captured, convert to a white hero after three turns.
Identifiers: Horde
Also, I realized the White Thomas Hunter's ability should be changed. The second sentence should instead be "May capture a Horde evil character of */4 or less to Opponent's Land of Bondage."