Cunning Opportunist

Most of your enemies may see the heavily armed and armored fighter, the shining paladin, or the savage barbarian as the greatest threat on the battlefield. That’s as it should be, for the Cunning Opportunist counts on being underestimated until it is too late. In taking a little time to examine your foes and your situation, you have an uncanny ability to take advantage of opportunities against your opponents that few others even notice. 

In addition to improving and varying your combat options, you eventually gain complete mastery in your chosen non-combat skills as well.

Analyze Defense

At 3rd level, you can choose one enemy creature within 30 feet of you. After you have spent one round of combat engaging the target, you have had a chance to analyze the creature’s movements and can pinpoint weaknesses in their defenses. While engaged in combat with the target, you can apply your Intelligence modifier to your attack rolls against that target in addition to the ability modifier you normally apply to your attack rolls. You can only target a single creature at a time with Analyze Defense, but you can choose a new target as a bonus action.

Precision Strike

Starting at 3rd level, if you are in a position to perform a Sneak Attack on a creature upon which you have used the Analyze Defense ability, you are able to forgo some of your sneak attack damage to inflict precision attacks with varying effects. These effects last until a healing effect is applied to the target (cure wounds spell, potion of healing, etc.) or a successful Wisdom (Medicine) ability check is applied to the target (DC 10 + half the damage dealt by the last successful Precision Strike). 

You can forgo 2 of your Sneak Attack damage dice to produce the following effects.

Arterial Strike. You cause the creature to bleed out. At the start of the target creature’s subsequent turns it takes 1 point of damage. Multiple Arterial Strike attacks result in cumulative hit point loss (two successful arterial strikes cause an extra 2 points of damage per round until healed, etc.).

Hamstring. You can reduce the creature’s base speed by one half (rounded down to the nearest 5 foot interval). This will also affect a creature’s burrowing or climbing speed, but flying, swimming, and other types of movement speeds are not affected by this effect.

At 9th level you can forgo 3 of your Sneak Attack damage dice to produce the following effects.

Concussing Strike. The target has disadvantage on attack rolls that use a Charisma, Intelligence, or Wisdom modifier, as well as Charisma, Intelligence, and Wisdom based ability checks. This effect lasts until the end of your target’s next turn.

Impeding Strike. The target has disadvantage on attack rolls that use a Dexterity or Strength modifier, as well as Constitution, Dexterity, or Strength based ability checks. This effect lasts until the end of your target’s next turn.

At 13th level you can forgo 4 of your Sneak Attack damage dice to produce the following effects.

Stunning Strike. The target must succeed on a Constitution saving throw (DC = 8 + half the damage dealt by Precision Strike) or be stunned until the end of your next turn.

Exhausting Strike. The target must succeed on a Constitution saving throw (DC = 8 + half damage dealt by Precision Strike) or receive one level of exhaustion. If you score a critical hit on this attack the target receives two exhaustion levels. Exhaustion levels can be accumulated over multiple Exhausting Strikes.

Caught Off-Guard

Starting at 9th level, you can use your reaction to make a single ranged weapon attack on any creature that has been successfully hit with an opportunity attack since the end of your last turn. You must be holding a ranged weapon to use this ability, and the target must be within your weapon's normal range.

Complete Expertise

At 13th level, your proficiency bonus is doubled for any other skill or tool proficiencies that you have obtained in addition to the Expertise applied at 1st level and 6th level.

Improved Sneak Attack

At 17th level, you can roll d8s to determine your Sneak Attack damage, and any 1s that you roll when determining Sneak Attack damage are counted as 2s.