Ok, only u have to have is a NPC Buffer(for cancel buffs) and a NPC for change class fast.
1step : with a friend or with ur 2cnd account u give u celestial shield(bishop class).
2seo ;: when u have celestial shield go fast cancel buffs and change subclass fastly
3set: u wil give u invincible
Tested in Interlude servers and 75% working
Pd: the NPC Buffer and the NPC change class have to be near >_> '