Maybe I’ve been reading too much paranormal fantasy lately, because you wouldn’t think this would be a thing I’d run into often enough to make me peevish. Nevertheless, I do, and it does.
Listen to me, people. Nephilim is not – I repeat, not – a singular noun. It’s a plural noun (that –im bit is the marker), and the singular is naphil.
The same goes for seraphim and cherubim. They’re plurals, too, and their singular forms are seraph and cherub, respectively.
If you’re going to mess around with Judaic and/or Christian esoterica, at least get the words right. (Or as right as reasonably possible, anyhow, given that we’re talking about words that wouldn’t have been written in the Roman alphabet to start with.)