This looks like an excellent Guardian upgrade. It's kind of similar to Magnifying Glass, in that it costs 1 resource, is Fast, and gives you +1 to your staple action for the rest of the game. That's great. Assuming you play this pretty early, it's going to way outshine what a skill card could accomplish.

The best use of this card, of course, is going to be sticking it on a Machete. That's the best level 0 Guardian weapon, and it works particularly well with Reliable since you can use Machete all game long, provided that the encounter deck doesn't discard it (something you should have been taking precautions against anyway). A multiplayer Guardian who specializes in monster killing (that is to say, most Guardians) can easily use a single Machete 10 times or more over the course of a scenario. That's a lot of value for 1 XP. If you don't draw your Machete, Reliable is also pretty good with the .32 Colt, or, for Skids and Leo, Switchblade II.

The doubled to-hit bonus is much appreciated on high levels. On Expert, you really want to consistently hit +4 (or sometimes +5) on your Combat checks. Prior to this card, that was quite difficult for most Guardians to reach. Now, it should be much more easily achievable. For Skids, who needs to overcome a mediocre base 3 Combat, this is an even bigger boon.

The fact that Reliable gives you a bonus to all skills, instead of just whatever you're testing, is intriguing. As the card pool currently stands, I don't think this really matters for any card except Lockpicks. But it's something to keep in mind as new assets come out.

Akachi can benefit from this card too, as it has charges and enters play with 1 charge thanks hes passive ability. Meaning that it refound it's cost as soon as you use that extra charge with the benefit of already having it in play. Also her Elder Sing trigger can put some charges on it and Recharge card can target this, so might be worth a try.

I think this card is hilarious. The fact that when other investigators are defeated you can be like, "Hey, silver lining; I got a charge on my Skull!" is priceless. Beyond that, I'm pretty sure this card is actually good; installs for an action, gains charges for doing something you'd do anyway, whether that's going through Ally assets or killing enemies, and pays back the action you took to install it after a single use. In a Leo Anderson deck, where you're losing allies and killing enemies in equal measure, the action compression this can give you over the course of a scenario, let alone a campaign, is pretty crazy. It may seem a bit slow, since it does take an action to use every time, but there are a lot of turns in a scenario where you might have an odd action that you "waste" just gaining a resource, and this makes those spare actions twice as efficient.

Does take up the Relic slot though, which is pretty valuable. Still, between The Watch and Lucky Dice, it's the only accessory Rogues have at 0xp. It'll be interesting to see it in action.

Also how weird is it that it's cursed, but doesn't actively harm you?

I think I really like this knife, surprisingly. It's certainly no Machete, but it does allow one more attack in a round than the Machete, and that attack has unconditional +2 and +1 damage, which is slightly better. I suppose your best case is to dual-wield, chopper in one hand and knife in the other, only using the Knife for its ability when available. Might actually make the Bandolier more attractive, since you can activate two Knives and hold a machete, or even get an extra free attack even with a Lightning Gun equipped. Knife + Bandolier + Zapper gets you 11 damage in a single round with 3 actions and no other cards; kinda crazy (and assuming everything hits).

As for the obvious drawback, soaking an attack, it turns out that an enemy attack always deals you damage, even if you assign that damage to your assets. Put another way, an effect that deals your investigator damage is always considered to have dealt you damage, even if you assign that damage to something other than your investigator. At least, if I'm understanding "Dealing Damage/Horror" on p. 7 of the Rules Reference correctly. What this means is, if you have your trusty Pooch out and, during the enemy phase, a Swift Byakhee attacks you, you can assign the damage to your excellent dog, triggering his effect, and trigger your Knife, taking no damage yourself and killing a 3-Health baddie without using an action. Furthermore, damage mitigation for Guardians is already pretty massive, so even without damage-soaking assets out the ability is pretty worthwhile. Weirdly, it doesn't work against enemies that only apply Horror, which isn't great, but those enemies are pretty rare anyway.

The more I look at it, the more I like it; I'll have to try it next time I make a Guardian. Probably best with Mark, as it synergizes with his love of taking damage, or with any asset-heavy fighter, like Leo Anderson.

How is this practically applied?? If, for example, I choose to upgrade Strange Solution, which has 3 available upgrades, do I put each copy of those available upgrades (ie 6 cards) facedown on the table and choose 2 of them at random??