The Royal Jelly Palace has frozen over and its king usurped by the true heir to the slimy throne, the frigid Ice Queen! She is a frost-themed version of the Tier 2 boss, Royal Jelly. She is one of the four bosses released with the Shadow Lair patch.
First you must reach depth 23, this can be easily done directly accessing Emberlight, then traveling through the Clockworks to D23. Once at depth 23, just walk past Basil to reach the Shadow Lair access area. In order to access the Ice Queen Shadow Lair, somebody in your party will need Shadow Lair Clearance Level 2, and somebody will need to use one Shadow Key to open the terminal for your party. (Only one Key is needed to give your entire party access to the Shadow Lair). Once you have opened the terminal, your party will be locked / closed and you won't be able to change the members (except to lose members) during the rest of the journey through the Shadow Lair.
This gelatinous giant is imbued with the fury of ice, yet the delicacy of Jell-O. While not quite as proper as an Impostocube, she is considered royal. Her attacks are incredibly similar to that of the Royal Jelly, yet stronger. Of course, you can always prepare! The Ice Queen herself shivers at the thought of poison, which restricts her jelly consumption. You can either use vials, obtained from the preceding levels, or weapons! Swords, while ever so useful, are a risky move, and you may want to prefer vials. While similar to the Royal Jelly, she does have some tricks of her own! Why, even being near this aristocratic abomination causes you to take damage! While a sword is not shunned, you may want to assault in quick skirmishes. Her fiendish little jelly friends stand in the way of guns, giving both aspects a challenge!
TL;DR: Bring poison and fire, be careful to get near her, she has a radius damage.
While she is known to be quite a royal pain, you can get around her tricks quite easily! She will periodically spin during the fight, which does cause serious damage. During this time, she is virtually invulnerable! Throughout the fight, she will regularly absorb the minis, giving her a constant stream of healing unless interrupted by poison. Of course, she does not create the lower class, rather she rules them! Those icy turrets in the background, Polyps, enjoy creating a streamline of these little freaks. If you can keep them down, you don't have to worry about the little jellies or the healing!
Being of a higher standing, she doesn't enjoy being crowded by lesser of people, especially knights! She will do a ferocious knockback to those who stand in her path. Again, this is best avoided by attacking in skirmishes.
Note! If she ever stops healing, and you have not poisoned her and she has Mini Jellies out and about, she may be full health. If this happens, pick up the pace and start dishing out more damage!
Note! Unlike the Royal Jelly, the Ice Queen is immune to curse, don't waste your time with curse vials or Gran Faust charge attacks!
TL;DR: Don't stand in her way, do a lot of damage, and kill the Polyps! Spinning may look fun, but it's not, don't stand in her way while she does that. She doesn't do any freezing.
Despite being a freeze-themed version of the Jelly King, the Ice Queen herself cannot inflict freeze during the boss fight: however, this matters little since her royal ice minis and royal ice polyps can both inflict freeze.