Arabelle

Bonus Proficiencies. The sidekick gains proficiency in one saving throw of your choice: Dexterity, Intelligence, or Charisma.

In addition, the sidekick gains proficiency in five skills of your choice, and it gains proficiency in light armor. If it is a humanoid or has a simple weapon in its stat block, it also gains proficiency in all simple weapons and with two tools of your choice.

Expertise. Choose two of the sidekick's skill proficiencies. The sidekick's proficiency bonus is doubled for any ability check it makes that uses any of the chosen proficiencies. 

At 15th level, choose two more of the sidekick's skill proficiencies to gain this benefit. 

Coordinated Strike. The sidekick is adept at fighting in concert with a companion. When the sidekick uses its Helpful feature to aid an ally in attacking a creature, that target can be up to 30 feet away from the sidekick, and the sidekick can do an extra 2d6 damage to it the next time the sidekick hits it with an attack roll before the end of the current turn. The extra damage is the same type of damage dealt by the attack. 

Evasion. Because of extraordinary good luck, the sidekick is skilled at avoiding danger. When the sidekick is subjected to an effect that allows it to make a Dexterity saving throw to take only half damage, it instead takes no damage if it succeeds on the saving throw, and only half damage if it fails. The sidekick doesn't benefit from this feature while incapacitated. 

Inspiring Help. When the sidekick takes the Help action, the creature who receives the help also gains a 1d6 bonus to the d20 roll. If that roll is an attack roll, the creature can forgo adding the bonus to it, and then if the attack hits, the creature can add the bonus to the damage roll against one target. 

At 20th level, the bonus increases to 2d6.

Reliable Talent. The sidekick has refined its skills to an exceptional degree. Whenever the sidekick makes an ability check that includes it whole proficiency bonus, it can treat a roll on the d20 of 9 or lower as a 10. 

Dagger. Melee Weapon Attack: +6 to hit, reach 5 ft., thrown 20/60 ft., one target. Hit: 5 (1d4 + 3) piercing damage.

Helpful. The sidekick is adept at giving well-timed assistance; the sidekick can take the Help action as a bonus action. 

Cunning Action. On each of its turns, the spy can use a bonus action to take the Dash, Disengage, or Hide action.