Got bored today, and after talking about design I decided to come back to this idea of mine. These ideas are all pretty rough, but thought i'd post the support I came up with for Ruby.
Ruby
7 HS
18 Vitality
Air Chaos Good
You may destroy foundations in your staging area to pay for the multiple costs on your weapon attacks.
E Commit 2 foundations: Your Weapon attack of difficulty 4 or less gets Multiple: 1.
Crescent Rose
Asset
2/5
Weapon
+2 Low Block
Air Chaos Good
E Flip: Your Weapon attack of difficulty 4 gets Multiple 1. Playable while committed.
R Commit: After you make a control check to play an attack, that check gets +2
Red Like Roses
Action
Air Chaos Good
2/4
R Remove: After your multiple copy deals damage, discard it from your card pool.
R Remove, discard 1 momentum: After your opponent plays a keyword ability, cancel its effects.
Weapon Nerd
Foundation
1/5
Air Chaos Good
+3 mid block
R Destroy: After your attack deals damage, your next attack gets +1 to its check. Playable only while commited.
RWBY's Leader
Foundation
2/5
Air Chaos Good
+3 low block
E: Your attack gets +1 damage for each multiple copy in your card pool.
R Flip: After your opponent plays a reversal, discard 1 attack from your card pool.
Gifted Child
Foundation
2/5
Air Chaos Good
E (4+): Your Weapon attack gets +1 damage
When this foundation is destroyed as a cost, add the top card of your deck to your staging area. Remove that foundation from the game at the end of turn.
Attacks:
Weapon Ranged attack
4/2
4 Speed high
4 Damage
+1 mid block
Air Chaos Good
Ranged Weapon Multiple 1
E: If this attack deals damage, your next attack of 4 difficulty or less you play gets Multiple 1.
Weapon Attack 1
4/3
3 speed low
4 damage
+2 high block
Air Chaos Good
Weapon Combo (high attack)
Combo E: This attack gets +2 damage for each multiple copy in your card pool.
Weapon Attack 2
3/3
2 speed high
3 damage
Air Chaos Good
Safe Weapon
E: If this attack deals damage, discard up to 1 multiple attack in your card pool.