Fighter/2nd/Captain

Knight's Conviction

If you use a technique or a fighter feature that calls for a saving throw, the DC is 8 + your Wisdom modifier + your proficiency bonus. If the feature already has a DC, you can choose to use this save DC instead.

Duel

Starting from 2nd level, you can use your bonus action to compel a hostile creature within 30 feet of you to focus on you. The target must be able to see you, though it need not be able to understand you. For 1 minute, the creature has disadvantage on attack rolls against creatures other than you. Additionally, each foot the creature moves away from you costs it 1 extra foot of movement.
     Any creature that can't be charmed also can't be affected by this feature.