About Korean Symbols
These thirteen characters are jamo: the individual consonant letters of Hangul, the Korean alphabet. They are letters in the same sense that B and D are letters, not symbols. That is worth stating because two of them are among the most-used pieces of Korean internet writing, and using them without knowing what they say is how a username ends up meaning something unintended.
ㅋ and ㅎ Are Laughter
ㅋ carries a k sound, and repeated — ㅋㅋㅋ — it is the standard Korean way of writing laughter, equivalent in use to "haha". It is extremely common in Korean chat, and more ㅋ generally means more amusement.
ㅎ is an h sound, and ㅎㅎ is a softer, gentler laugh — closer to a chuckle than to laughing out loud. The two are not interchangeable in tone.
ㅇㅇ is another everyday one: it functions as a casual "yeah" or "yep". None of these are obscure — they are ordinary informal Korean, and a Korean speaker reads them instantly.
Why They Stay Separate Instead of Forming Syllables
Korean is normally written in syllable blocks — consonants and vowels combined into a single square unit, like 한. The characters on this page come from a compatibility block that holds each letter as a standalone form specifically so it can be displayed on its own.
That is why pasting several in a row gives you a line of separate letters rather than a syllable. It is the intended behaviour of these particular code points, not a rendering failure.
Shapes Worth Borrowing
ㅇ is a clean circle — silent at the start of a syllable, an ng sound at the end — and its simple geometry makes it the most usable here as pure decoration. ㅁ is a square and ㅅ a shape close to a caret or a small roof.
All thirteen are plain text characters that inherit the colour and size of surrounding text, and Hangul coverage is standard on modern systems. For related decorative punctuation, the Chinese bracket characters and the Japanese symbols cover the neighbouring blocks.