He was Data Drained by Skeith in an Avatar battle. That counts.There's no sign of Endrance ever being DDed, being DDed doesn't leave you frozen at the bottom of a lake.
Maybe a really badass AIDA. Or the "It" That is unlike any class of entity ever seen in the World or the true enemy beyond all imaginationWell, I'm still waiting since I'm pretty sure the full explanation will be much more complicated than that... Tri-Edge's data drain in Roots would have destroyed it if it was just an AIDA...