New Class Abilities

Social Combat Stats
Multiclass characters use the Defense & Damage from one class; they don't add. They can switch which class they're using ("changing the style of argument") as a bonus action.

Ranger
"Argumentum Ad Baculum""1st level enchantment""Casting Time: 1 action""Range: 30 feet""Components: V""Duration: Concentration, up to 10 minutes""You issue a challenge to a creature engaged in social combat with you. If the target fails a Charisma saving throw, it accepts your challenge and agrees to resolve the disagreement with the physical contest you described in your challenge. If the contest seems fair, it has disadvantage on the saving throw.""At Higher Levels: When you cast this spell using a spell slot of 2nd level or higher, you can target one additional creature for each slot level above 1st. The creatures must be within 30 feet of each other when you target them."

Old stuff below this line; kept for ideas.
When using this system there are new abilities for classes at 1st, 5th, 10th, and 15th levels.