OUTDATED, read this for 6.2: http://atributetomadskill.blogspot.se/2016/03/time-lost-proto-drake-62_20.html
Okey, so i found vyragosa at 01.11. She despawned exactly 01.41, wich makes me think that there is a set timer on this. I am gonna go back at 07.11 and now start camping for time lost!
Update; I found a dead corpse of Vyragosa 11.19 (10 hours 8 min after i killed her)
WOOOOOOOOOOOOOOOOOOOOOOTTT!! NPCSCAN POPS UP 21.20, WHO IS IT?