I wonder if these expressions are okay.

I remember him because his Korean name is unique.
I remember him whose Korean name is unique.
I remember him because of his unique Korean name.
His Korean name is so unique. That's why I remember him.
His Korean name is so unique to a point where I can't forget him.
The uniqueness of his Korean name has been engraved him in my brain.
He has a unique name. That's why I remember him.


The basic meaning is the same but I wrote those sentences in various ways.

How about that?
Everything is okay?

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Other than some improvements, your sentences are very good! :)

I wonder this expressions are okay.

X I remember him why he's Korean name is unique.
O I remember him whose Korean name is unique.
O I remember him because of his unique Korean name.
O His Korean name is so unique. That's why I remember him.
O His Korean name is so unique that I can't forget him.
X The uniqueness of his Korean name has engraved him in my brain. (see below)
O He has a unique name. That's why I remember him.

"The uniqueness of his Korean name has led/caused him to be engraved in my brain."

-> This sentence is quite weird and not very academic. The word "engraved" is not commonly used in this context. Usually it would refer to something or someone you will NEVER forget or something/someone you think about all the time. For example, "That scary image of the monster was engraved into my brain, I'm afraid that I will never be able to forget it."

For the rest of the sentences, you did really well! Good job:)

The basic meaning is the same but I wrote those sentences variously.

How about that?
Everything is okay?