This deity was originally red in colour and burning fire is also red.
kan > kanal.
kan > kanal > kanaluthal. (burning).
kan > kanalal (burning).
kan + thu(suffix) + an (masculine suffix) = kanthan.
Kanthan was later introduced to North India by the Tamil devotees. Then:
kanthan > skanda.
kanthan > iskandar (in Malay and Indonesian). Now a name of many a Malay and Indonesian.
Skanda a South Indian deity.
kukai > kudai > kuzai.
The root is kuL.
Examine: paL – depression in the ground.
paL > paLLam – depression in the ground.
paL > padukai. depression in the ground.
So, paL can change to padu.
paL also can change to paku. (to split, to divide). paku+ ai = pakai.
Is the rule of change clear? Words change in similar pattern in Tamil.
kuL > kukai ; kuL > kudai , (also kudam, kudavu(kukai). kuL > kuzi > kuzal >kuzaai.
Now we tabulate:
kuL >(kuku)*> kukai like paL >( paku)* pakai
kuL > (kudu)* > kudai like paL > (padu)* >padukai. (kudu) > kudavu. also kudaivu.
kuL > kuttai ; kuL > kudu > kudam.
kuL > (kuku)*> kukan ( person of the cave or kudavu).
kuL >( kuku )> kukam (kuham) a cavern.
kuku – a tubular vessel of the body.
kuhan (kukan) was a name applied to Kanthan,
kudavu = a dance of kanthan.
kudagu malai is a malai with a lot of kudavu or caves.
There are too many derived words in this area from the great root word kuL.
Many millenia must have gone by for the words to undergo such multiple changes.
Modern languages do not show such multiple changes and acceptance(joining) of suffixes.