Rather symbolic name.
It means "To mock the Darkness"
Sy- To Mock
Noct is obviously a shortened version of the word, "Nocturnal" which means Dark.
He is a Chaotic, Good character

Synoct was a simple boy who became a demon to kill demons.
Using spells and weaponry from them as well to do these deeds in the name of sweet revenge.
He was a boy who was raised in an orphanage after his parents where killed by Fiends who attacked his village.
Too young to remember the entire incident only to realize it when the caretakers spoke of it in private while sneaking around for some snacks. On his 14th birthday, he left the orphanage and wandered into a magic shop and stole its tomes, stumbling upon a summoning book that could summon demons. He summoned a Lord type and made a bargain for some powers only to kill the lord type moments later. Decades go by however his life span is lengthened thanks to the powers he has at his disposal. Now he wanders in search of the demons that killed his parents and destroyed former home.

His theme is Hopes & Dreams
Abit fitting for a boy who only seeks vengeance to what wrongly done to him.