The デレ is a real word, not an invented suffix. Japanese carries a huge stock of mimetics for manner, and デレデレ is an ordinary member of it: soft, fawning, visibly melting over someone. Fandom clipped it to デレ and turned it into a suffix — so every type in the family means ⋯ on the outside, soft underneath, and only the first half changes.
ツンデレ and ヤンデレ are near-opposites. ツン is from ツンツン, prickly — the coldness is armour, the affection is underneath, and the arc is a thaw. ヤン is from 病む, to fall ill — the affection is on display and it is the affection that has gone wrong, so the arc is a descent. English discussion blurs the two constantly; the Japanese keeps them apart in two morae.
クーデレ and ダンデレ differ in what the barrier is made of. A クーデレ is クール: flat, unreadable, apparently indifferent — nothing is being pushed away, there is simply nothing showing. A ダンデレ is 黙り, silence: they would speak if they could. Cold on purpose, blank by nature, and mute from nerves are three different characters, and the first mora tells you which.
ヤンギレ is the one with no デレ in it. 病む ＋ キレる, to snap: someone who turns violent without the devotion that defines ヤンデレ. It is the clearest proof that the デレ is load-bearing — take it out and the archetype changes rather than weakening.
They are fandom vocabulary of recent coinage. All of these were made on Japanese message boards in the 2000s, with ツンデレ first and the rest modelled on it. None appears on a JLPT list. Japanese speakers inside anime and game circles use them freely; outside, many will recognise the words without ever reaching for one — and about a real person ツンデレ is teasing while ヤンデレ says they are dangerous.
