Disclaimer: Pre-Scarlet Keys release review.

Another niche card that is a bit hard to understand for now. Tactic is one of the least interesting Trait since it only matters for Mark Harrigan but he already accesses 0-5, Chuck Fergus (so "Skids" O'Toole) but it's already fast and doesn't involve a test, Directive - Red Tape but again it's already fast and Sleuth but it's probably one of the least interesting 3-class talent.

So, why would you ever use this card??

The main issue is "At the end of the round", meaning after the enemy phase.

• Daniela Reyes can automatically evade an enemy with her . Trigger it with the Mechanic's Wrench and attack with it, applying the wound. Since your turns are often a bit empty, applying a DoT to an enemy and leaving to engage another one is potentially really good. And on top of that, lvl 0 cards are not so hard to slot in her.
• Survival Knife (0) if, for some reason, you are already considering getting some hits, you can now do so with a 3-hp enemy and kill it after you get attacked. It's not great, but if you planned on taking the Survival Knife already, then it's worth considering.
• Butterfly Swords allow you to perform the first attack on an enemy and the second on another one. So you could technically do the smaller attack combined with Grievous Wound on a bigger enemy and the 2-damage attack to defeat a 2-hp enemy and evade the wounded enemy. That is a veeeery niche situation since it requires you to have 2 enemies in play, one that justifies this and that you are able to evade after... Let's see what other cards come in this pack. As of now, I see an opportunity here, but not enough yet for something viable.
• As suggested in the comment by @Veronica212, "Skids" O'Toole could be somehow a bit interested, as he is more able than others to evade and leave the DoT behind. Cheap Shot (2) is a good way to add 1 damage and exhaust, and Switchblade, Enchanted Blade without using a charge as suggested. It doesn't save you much time unless you can change location and the enemy is not a hunter.
• In the same vein, William Yorick could see use with Stunning Blow, attacking with a Gravedigger's Shovel, Fire Axe without going down to 0 resources, Meat Cleaver without spending the Horror, etc... The problem is that you need both Stunning Blow and Grievous Wound in your hand at the same time, which can be complicated with the little Draw ability of Yorick.
• Honorable mention to Trusty Bullwhip would have been nice with this since you can attack, exhaust to evade and apply the bleeding.

Conclusion: As of now, except for Daniela Reyes, I wouldn't really consider this card yet, but that may change in the near future!

A terrible card that is actually somewhat useful in Hemlock Vale.

Enemies in HV have Elusive, meaning they disengage and move away after getting smacked once. Some of them have 5hp. Grievous Wound solves that problem.

As another review said, perfect for alternate Pete because it can be recurred every round, and also situationally nice for alternate Zoey, if you can stick it on a beefy enemy and let it bleed blesses into the bag for several rounds.

This card is hard to use for most guardians, but it seems custom-built for Parallel Ashcan Pete. It's a nice solution to 3+ health enemies for him.

You attack a 3 health enemy, attach Grievous Wound, and then move the enemy away for free with his Guitar. The guitar gives you a resource, which refunds the cost of Grievous Wound.

At the end of the round, the enemy takes 1 damage and dies, and Grievous Wound returns to your hand. You can do this infinitely to kill 3 health enemies in a single melee attack, as a kind of reusable Vicious Blow.

It could even kill bigger targets like a Deep One Bull, although you probably want a nice trap to keep it from moving while it bleeds out (like Snare or Net from Makeshift Trap).

This card is a great example of Power creep, and why it prevents the use of newer cards.

This card is in direct competition to vicious blow, and begs the question "why would I ever use this over vicious blow?"

The short answer there is that you won't. Everyone that can take this card can also take vicious blow, and vicious blow outperforms this in all scenarios.

What about taking it AND vicious blow? I could see some use in the fighter style characters without access to the heavy hitting guardian weapons. Yorrick and Silas come to mind right away. But you still have to wait for this card to take effect, meaning the enemy will most likely get an attack off. This somewhat defeats the purpose of attacking the enemies then. Most enemies have 3 HP, and the ones that have more usually have 5-6. So you do a vicious blow augmented standard attack on a 5-6 HP enemy, and it lives and your turn ends. The enemy attacks you and then this ticks. So the enemy now has ~4 damage on them. This translates to you having to attack the enemy again your next turn to finish them off, or leaving them evaded for two turns someway to make this card eventually run its course. You very quickly then get into a Rube Goldberg style problem with "why didn't you just kill it with another attack", which begs the question again of why did you take this card.

So when do you use this card? The only reasonable excuse I could see would be on enemies with exactly 4 HP, using an investigator with smaller arms and probably that also has stunning blow and can outmove the hunter keyword.

It ends up being a lot of very specific criteria to make this card worthwhile, so I can't honestly say it has a place in any deck.

If future upgraded versions had a draw attached to it, we may be talking though.