They have some abilities that Ready their characters, so Mulan Charging Ahead will be very useful Unfortunately, they also have a couple of very effective strategies against your Challenger-focused deck
While it does have the downside of inflicting a negative Special Condition, which can be cleared, it compensates for what can be an immediate outburst of power
Froslass W - Snow Jail 20+ If you played Candice from your hand during this turn, this attack does 90 more damage and your opponent's Active Pokmon is now Paralyzed
Active Pokmon can retreat once per turn
The ability to exile specific cards is always useful, and this engine becomes more dangerous the more you use it
If "Visas Starfrost", or a monster with 1500 ATK/2100 DEF, you control would be destroyed by battle or card effect, you can banish this card from your GY instead