Understanding a TCG card effect

Question

I've been translating a trading card game in my spare time, and while the majority of it has gone smoothly, there've been one or two places where I've either hit a grammar point I'm completely unfamiliar with or am just parsing horrible wrong. Probably the best example is the card effect given here:

戦闘力が使用キャラカードの戦闘力以下のキャラカードを１枚撰び、捨札置場に置く。このカードはアクション中に使用できない。

My current translation reads as follows:

Choose a Character card with equal or less power than the one using this Skill card and discard it. This card cannot be used during an Action.

My big stumbling block comes from the first part of that first sentence, 戦闘力が使用キャラカードの戦闘力以下のキャラカードを１枚撰び. I'm getting all snarled up trying to follow what's modifying what. Am I close in interpreting the text? Or not? Could someone show me how all the modifiers are working here?

(Extra context: A Character card is a type of card that has a 戦闘力 value. This number is compared to another Character card's 戦闘力 when they fight, and the one with the higher number is the winner. The effect given here is from a Skill card, which a Character card uses.)

Answer 1

I've played some card games, but not this one so I could be off a bit, but my translation would be: Choose one character card with a combat power equal or less than that of the user, and discard it/place it in the graveyard. This card can not be used during an action.

I'm not too good at explaining but hope this makes sense.

戦闘力が使用キャラカードの戦闘力以下のキャラカードを１枚撰び。

使用キャラカード　is referring to the character card that is using the skill card.

以下 means equal or less than

一枚選び means choose one (of something that is counted using the 枚 unit, ie cards).

So,

1. The の in 使用キャラカードの戦闘力 indicates possession of the 戦闘力　trait by the 使用キャラカード。

2. The が is indicating the condition / property of the 戦闘力 trait (beginning of sentence). The condition / property is that it is 使用キャラカードの戦闘力以下

3. The second の in 戦闘力が使用キャラカードの戦闘力以下のキャラカード indicates possession of the 戦闘力 trait, described in the above bullet, by the キャラカード。

4. を is used to represent the target of the verb, in this case 一枚選び。The target is 戦闘力が使用キャラカードの戦闘力以下のキャラカード.

So, with the above in mind, the target of the verb (一枚選び) is the キャラカード, who possesses a 戦闘力 trait that is equal or less than that of the 使用キャラカード (使用キャラカードの戦闘力以下).