Yi Ki-seop

(b.1950) Korean pro, 5 dan in 1992.

He may well be Go4Go's "Lee Kisup", 8p since at least 2017.

However, Go4Go has no earlier games and he could not be found on PWD (under either SL's or Go4Go's romanisation, or indeed several others).

In any case, he may have now retired. "Lee Kisup" has his most recent kifu dated 2020, though, so this seems a little unlikely.