itoko ga yakitori wo katte kite kureta node, watasi ha karaage wo tukuranakute sunda.

Here, いとこ が marks my cousin as the subject of the first clause:

• いとこ が 焼き鳥を買ってきてくれた
• My cousin bought and brought yakitori for me

Using が is natural because it identifies who performed the action. In this sentence, the cousin is the one who did the helpful action.

If you used は instead, it would sound more like you were setting up my cousin as the topic, possibly with a contrastive nuance.

This is a combination of three parts:

• 買って = te-form of 買う (to buy)
• きて = te-form of くる (to come)
• くれた = past form of くれる (to do something for me/us)

So:

• 買ってきた = bought it and brought it here
• 買ってきてくれた = bought it, brought it here, and did that for me/us

The important nuance is benefit to the speaker.
くれる shows that the action was done as a favor or in a way the speaker appreciates.

So this is not just my cousin bought yakitori. It is more like:

• My cousin kindly bought some yakitori and brought it over (for me/us).

Because the sentence is chaining multiple actions/functions together.

1. 買う → 買って
2. くる → きて
3. くれる → くれた

The structure is:

• 買ってくる = go buy / buy and bring back
• 買ってきてくれる = do the favor of buying and bringing back

So the two て forms are not random. They connect the verbs step by step:

• buy → come/bring → do for someone

This kind of verb stacking is very common in Japanese.

Both can mean because/since, but the nuance is a little different.

• ので sounds a bit more neutral, explanatory, and softer
• から can sound more direct or more like the speaker’s personal reasoning

In this sentence:

• いとこが焼き鳥を買ってきてくれたので、私は唐揚げを作らなくて済んだ。

ので sounds natural because the first clause is giving the reason for what happened in the second clause.

A rough comparison:

• ので = since / because (as an explanation)
• から = because (that’s why)

Both are possible here, but ので feels slightly smoother and less blunt.

This is a very useful grammar pattern:

• verb-negative て form + 済む
• Vなくて済む = to get by without doing V / to not have to do V

So:

• 作る = to make
• 作らない = not make
• 作らなくて = without making
• 済んだ = it was settled / it was enough / it ended up being okay

Together:

• 作らなくて済んだ = I didn’t have to make it
• more literally: It was settled without needing to make it

So the speaker is saying that because the cousin brought yakitori, making karaage became unnecessary.

Both 〜なくて済む and 〜ないで済む are used, and both can mean to not have to do something.

So both of these are possible:

• 作らなくて済んだ
• 作らないで済んだ

In many cases, the meaning is basically the same.

That said:

• 〜なくて済む is extremely common as a set expression
• 〜ないで済む can sometimes feel a little more like without doing X

For learners, the safest takeaway is:

• Vなくて済む = very common pattern meaning not have to V

So the sentence is completely natural as written.

私は marks the speaker as the topic of the second clause:

• 私は唐揚げを作らなくて済んだ
• As for me, I didn’t have to make karaage

This helps make the contrast in roles clear:

• the cousin did the buying/brining
• I was the one who benefited and therefore did not need to cook

Japanese often omits 私, so this could also be left out if the context were clear. But including 私は makes the sentence easier to follow and can add a slight contrastive feeling:

• because my cousin did that, I didn’t have to do this

Because both are the direct objects of their verbs.

• 焼き鳥を買ってきてくれた
  • bought/brought yakitori
• 唐揚げを作らなくて済んだ
  • didn’t have to make karaage

So:

• 焼き鳥 is what the cousin bought
• 唐揚げ is what the speaker would otherwise have made

The particle を marks the thing directly affected by the action.

いとこ is gender-neutral. It can mean:

• male cousin
• female cousin

Japanese does not distinguish them in the basic word. If necessary, the speaker can clarify with extra information, but いとこ by itself does not tell you the cousin’s gender.

Literally, 焼き鳥 means grilled chicken, but in actual use it often refers to the Japanese food yakitori, usually skewered grilled chicken.

So in a sentence like this, it most likely means:

• yakitori
• grilled chicken skewers, or yakitori items bought prepared from a shop

It does not usually mean homemade plain grilled chicken in a generic English sense.

These verbs depend on whose point of view the sentence uses.

• くれる = someone gives/does something for me/us
• もらう = I receive something / receive someone’s action
• あげる = someone gives/does something for someone else

Here the speaker is describing the cousin’s action as a benefit to the speaker, from the speaker’s point of view:

• いとこが…買ってきてくれた
• My cousin bought and brought it for me

If you used もらった, the sentence would need a different structure, such as:

• 私はいとこに焼き鳥を買ってきてもらった
• I had my cousin buy and bring yakitori for me / I received that favor from my cousin

So くれた is correct because the cousin is the subject and the speaker is the beneficiary.

Yes, very naturally.

The phrase 作らなくて済んだ strongly suggests that making karaage was expected, necessary, or at least likely before the cousin brought yakitori.

So the nuance is something like:

• I was going to have to make karaage, but because my cousin brought yakitori, that became unnecessary.

This implication is one reason the sentence sounds very natural in everyday Japanese.