The North
Characters lose all immunities.

Any Phase: If it is not the marshalling phase,kneel 3 influence and discard Den of the Wolf from play (cannot be saved) to repeat the current phase at the end of the phase. (Limit once per game.)

If you repeat the "Current Phase" and you choose the Challenge phase, is it essentially starting a brand new challenge phase (so all the effects that would have worn off at the end of the first challenge phase expire?) or are you just extending the current phase for 2x its normal duration (and effects that remove icons or reduce STR until the end of the phase endure?)

Since the End of the phase still happen (Den of the Wolved do not replace it), all the effects "until the end of the phase" will wear off. It is a new phase not an extension of the same phase.

I figured as much since it doesn't say "Continue the current phase" ...just wishful thinking on my part

~Uh-oh, now I need anti-Den meta in my decks for Kubla? The least played Champ card of all time?

Haha Rings, I was thinking "I need anti-Viper meta in my decks for Kubla" ...cue the Den!