The Kensei's level 6 features seem lackluster compared to other ways of spending a ki point; what is its niche?

Question

The Way of the Kensei monk gets the One with the Blade feature at 6th level (Xanathar's Guide to Everything, p. 34-35):

At 6th level, you extend your ki into your kensei weapons, granting you the following benefits.

Magic Kensei Weapons. Your attacks with your kensei weapons count as magical for the purpose of overcoming resistance and immunity to nonmagical attacks and damage.

Deft Strike. When you hit a target with a kensei weapon, you can spend 1 ki point to cause the weapon to deal extra damage to the target equal to your Martial Arts die. You can use this feature only once on each of your turns.

So at level 6 a monk would use a ki point to add 1d6 dmg? This is instead of a Stunning Strike or Flurry of Blows? Is the damage bonus continuous through the turn with further weapon strikes?

Answer 1

It gives you an extra opportunity to spend a ki point for one extra martial arts die's worth of damage (potentially ranged) per turn

You seem to have two major concerns:

1d6 is rather little damage compared to the other available ways to spend a ki point

The damage potential of Flurry of blows is no doubt a lot higher, and the way it is written it clearly applies to only a single attack. However, Deft strikes' trigger is when you hit with a kensei weapon, which means there are some trade-offs that can potentially make Deft strikes situationally good:

1. The extra damage is guaranteed
2. This can be used after you land a critical hit, which would double the dice
3. You can deal the damage at range, if the weapon you're using is ranged
4. Extra damage is extra damage. If your target needs to go down now, this might make a difference

When the Martial Arts 1d6 die becomes up to a 1d10 later on, it obviously does so too for the extra attacks from Flurry of blows, so that's a moot point.

You can use both Flurry of blows and Deft strikes in the same turn

Flurry of blows allows you to spend one ki point to make two unarmed strikes as a bonus action. The trigger for it is: "after you take the Attack action on your turn". Nothing bars you from still doing so after using Deft strikes.

Answer 2

This ability basically gives the monk a variation on the Paladin's Smite. Instead of a spell slot, you spend ki, but it grows with the levels at the same cost, whereas smite can only be increased by spending more powerful spell slots. Also, you can do it more often, since ki recharges on a short rest.

Answer 3

Given that Kensei Monks are forced to take a ranged weapon as one of their Kensei Weapons, we can assume that Kensei Monks are intended to be reasonable ranged attackers -- I believe Deft Strike exists mostly to support that. Most of the other ways to spend ki at level up until level 11 either require (Stunning Strike, Flurry of Blows) or are most useful (Dodge/Disengage) in melee situations, which most bow users try to avoid (and monks would be generally better at that with the +15ft movement they'd have at level 6).

Deft Strike allows a ranged Kensei Monk to spend Ki to increase their damage. Seems a welcome option. Allowing melee monks to use it for the few situations where immediate guaranteed extra damage is helpful is just icing on the cake.

Answer 4

I'd agree that it seems underwhelming and inefficient compared to other options (e.g. Flurry of Blows) in most cases. The only benefit I can see is that it allows you to burn Ki points to deal a burst of extra damage, at the cost of long-term damage. This would usually be inefficient use of resources, but if you're ever in a scenario where you need something dead right now that extra 1d6 per turn could help kill it faster.

Answer 5

Deft Strike only applies to one hit

Deft Strike notes that spending 1 ki point on a hit with a kensei weapon causes the weapon to deal an extra 1d6 damage, and that "[y]ou can use this feature only once on each of your turns." If the rule expressly forbids using the feature more than once, the implication is that you would have to use the feature more than once for it to apply to more than one hit. Hence, it only applies to a single weapon strike.

In addition, Deft Strike does not require an action, so there's nothing preventing a Way of the Kensei monk from using it alongside Flurry of Blows besides their number of Ki points remaining.