Queen midwinter doesnt spawn anymore too
She wasn't technically a boss, she was just a quest mob, same as the Tree and Stag are in the current event.
I believe that theoretically, all bosses that were ever in this game have a chance of spawning. It is just very, very, very, very, very, very, very,very rare.
That's true, except for the Halloween 2011 bosses, the rest are still in the game. OTM decided after the 2011 Christmas event to have the bosses respawn rarely so people can still complete their Connacht sets, even though it would take decades. Then all bosses afterwards simply followed suit.
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