My online handle is still Kairos and you can still call me that and I'm not changing my name anywhere else and I'm keeping my header. But without an underscore it turns out "Kairos Imperfect" was a bit of a confusing mouthful, plus I was bored with it.
"Perpetual" is just a word I've always liked. It bears some relation to my love of gargoyles and the race of sentient gargoyles that lives in my fiction. I think of them as Perpetuan gargoyles.
I like things that last forever. LJ usernames don't, but I like that, too.