Well, since there is a boss that deals fire, shock, and stun, why not frost for normal T3? Frost empress- Lady Helia? ( Helium-arguably coldest substance at solid form, while Vanaduke comes form the element Vanadium, which has very suprisingly coincidential colors!)
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Physical Appearance:
Mainly 3 body segments (Bipedal): Heavy top segment (which holds Stubby yet wirey arms that have domes on the ends, her head which is mainly a crown, and 4 pillars) Small midsegment, and Large, dresslike, bottom segment. Her uppersection and head emit a frosty mist and a dark purple mist, showing she is not completey mortal. Her room is... well... and Icy version of Vanaduke's room.
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Helia is generally the same as Lord Vanaduke, except she's Vanaduke's royal rival. Plus, she causes curse. Maybe Fire beats Ice, but try taking on Curse!
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Battle: like Vanaduke, Helia has five phases.
1. As a large opponent, she slowly walks forward and blasts several icy projectiles form her dome arms that would cause freeze. When a player is near, she would give a powerful twirl, like the Royal Jelly, to shove the knight away. After some time, she would start charging at a group of knights, like what Trojans and Vanaduke do, with a spear that emerges from a dome. After like 3 rushes, she goes back to shooting away.
2. She summons Frost Walkers while she blasts away, and she herself does not charge in this phase, but instead, while she twirls when a knight is close, she shoots stray spikes in random aiming.
3. Here, her dome arms cover her body and mid-segment and stays still in the middle of the arena, but her pillars fall forward at each of her sides. She cannot at all be harmed in this stage. She again summons- not Frost Walker- a Slag Guard's icy opposite- A zero guard. A nasty swipe of these guys could leave a weak curse or freeze, but their attempt is not to destroy you- but to heal the Lady. Six guards spawn, for go to each pillar and stay there and heal her from there. the knights must destroy all guards (which drop only hearts) in a certain amount of time before Helia is recharged at a certain point. When all are dead in time, she gets up and gives a mighty scream, which stuns all knights not shielding and drops a lot of debris from the cieling. If not successful at killing the guards in time, she reverts to phase 2, and must redo the process again.
4. Almost another Bezerk Mode. She first pounds at four ways with her pillars and twirls across the room, stunning anyone that gets in her way while pushign the knight and dealing much damage. She also randomly blasts ice orbs while in this mode. Unlike the Royal Jelly, she is completely vulnerable to anything except curse and freeze.
5. She is outraged. Helia must not be defeated by midgets! Four pillars down, they extend to divide the room into four quadrants. In those quadrants, the knights are stuck. Her mid section goes into her bottom section and her arms fold upward, giving a pinnacle type of shape. The four pillars then become frost-stricken, and debris falls randomly. Her head flies off her body, and curses AND freezes every knight it hits, constantly moving. To make matters worse, her head shoots ice orbs forward at all times which could freeze the knight and those pillars- yeah, you cannot touch them or you freeze. Once the head is at a certain amount of health, guards rise, one at each quadrant, and the head is not aiming for a certain knight, but just going berserk, debris still falling from the sky. Finally, it is destroyed after knights give it their final might. Helia's head breaks apart, and the body goes back intact like the beginning of the battle. A shriek, and the body falls over and decays like the normal boss. The battle is over, and the knights have won.
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Abilities and weaknesses:
Abilities:
-Berzerk Mode
-Quadrant Mode
-Summon
-Static Heal
-Ice Spear
-Ice Blast
-Headless
-Royal Twirl
-Invulnerability
-Pillar Pound

Weaknesses:
I do not think Lord Vanaduke has a certain damage weakness. As his tier counterpart, I do not think Helia should have one either.
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Token Rewards: (She gives Celestial Ice tokens)
-(20) Skolver's Claw 4* [Ice FangofVog]
-(20) Cold Soldier Suit 4 * [Icy version of Cobalt] (Turns to Ancient Ice)
-(20) Cold Soldier Crown 4* [Basically Ascended Cobalt Helmet, with a royal ice finish] (Turns to Emperor's Crown)
-(25) North Star 4* [Ice Heavy Plate Shield] (Turns to Orion's Shield)
-(105) Dry Ice 2* [Icy Crystal Bomb] (turns to Nitrogen Bomb, then Dry Nitrogen bomb)
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