Lytfir

The normal process of this encounter is to get him down to about 40% and, when he becomes invulnerable, use the crystal to put him to sleep.
For , rumor says that to KILL Lytfir, DO NOT USE THE CRYSTAL! You need to 1-shot him from ~50% to 0, OR burn him like The Towering Inferno until his invulnerable shield is destroyed. This is not confirmed.
You can obtain the illusion of this monster (and some stat boosts) by using or .
This was the 3rd Boss in the first year of this event.